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                                                                    EXHIBIT 10.6

                  GUARANTY OF NEXSTAR FINANCE HOLDINGS, INC.
                  -----------------------------------------

     This GUARANTY (this "Guaranty"), dated as of January 12, 2001, is made by
                          --------
Nexstar Finance Holdings, Inc., a Delaware limited liability company (the
"Guarantor") in favor of the Guaranteed Parties (as hereinafter defined).
 ---------

                                   RECITALS:

     A.   Nexstar Finance, L.L.C., a Delaware limited liability company (the
"Borrower") is a party to that certain Credit Agreement, dated as of January 12,
 --------
2001 (as the same may be amended, supplemented or otherwise modified from time
to time, including, without limitation, all extensions, renewals, restatements,
rearrangements and refundings thereof, the "Credit Agreement"), among the
                                            ----------------
Borrower, Nexstar Broadcasting Group, L.L.C., a Delaware limited liability
company (the "Parent"), certain Subsidiaries of the Parent from time to time
              ------
parties thereto, the several financial institutions from time to time parties
thereto (the "Banks"), Bank of America, N.A. as Administrative Agent for the
              -----
Banks (in such capacity and together with its successors in such capacity in
such capacity, the "Administrative Agent"), Barclays Bank PLC as Syndication
                    --------------------
Agent and First Union National Bank as Documentation Agent, pursuant to which
the Banks have severally agreed to make loans to the Borrower, and Bank of
America, N.A. (the "Issuing Bank") has agreed to issue letters of credit for the
                    ------------
account of, the Borrower, upon the terms and conditions set forth therein.
Capitalized terms used but not defined herein have the meanings assigned to such
terms in such Credit Agreement.

     B.   The Borrower may also from time to time be party to one or more
Interest Rate Protection Agreements with any Bank or an Affiliate of any Bank
(even if any such Bank ceases to be a Bank under the Credit Agreement for any
reason), and their successors and assigns, if any (collectively, the "Interest
                                                                      --------
Rate Guaranteed Parties"), providing for protection against fluctuations in
-----------------------
interest rates.

     C.   As a condition precedent to the extensions of credit under the Credit
Agreement and the Interest Rate Protection Agreements, the Banks have required
that the Guarantor execute and deliver this Guaranty in favor of the Banks, the
Issuing Bank, the Administrative Agent, the Collateral Agent and the Interest
Rate Guaranteed Parties (collectively, the "Guaranteed Parties").
                                            ------------------

     D.   The Guarantor will derive substantial direct and indirect benefit from
the extensions of credit under the Credit Agreement and the financial
accommodations under the Interest Rate Protection Agreements.

     E.   Accordingly, the Guarantor desires to execute this Guaranty in order
to satisfy the condition described above in Recital C.

     In consideration of the foregoing and for other good and valuable
consideration, the receipt and adequacy of which are hereby acknowledged, the
Guarantor hereby agrees as follows:
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     1.   Guaranty.
          --------

          (a)  The Guarantor unconditionally and irrevocably guarantees the
prompt payment when due, whether at stated maturity, upon acceleration or
otherwise, and at all times thereafter, of all the unpaid principal of and
interest on the Loans (including, without limitation, interest accruing after
the maturity of the Loans and interest accruing after the filing of any petition
in bankruptcy, or the commencement of any insolvency, reorganization or like
proceeding, relating to any Credit Party, whether or not a claim for post-filing
or post-petition interest is allowed in such proceeding) and all other
obligations and liabilities of the Borrower to the Administrative Agent, any
Bank or the Issuing Bank (or in the case of any Interest Rate Protection
Agreement, any Affiliate of any Bank), whether direct or indirect, absolute or
contingent, due or to become due, or now existing or hereafter incurred, that
may arise under, out of, or in connection with the Credit Agreement, any other
Loan Document, any Letter of Credit, any Interest Rate Protection Agreement
entered into with any Bank (or any Affiliate of any Bank), or any other document
made, delivered or given in connection with any of the foregoing, whether on
account of principal, interest, Guaranty Obligations, reimbursement obligations,
fees, indemnities, costs, expenses (including, without limitation, all fees,
charges and disbursements of counsel to the Administrative Agent or to any Bank
that are required to be paid by the Borrower  pursuant to any Loan Document) or
otherwise (collectively, all of the foregoing are referred to herein as the
"Guaranteed Obligations").
 ----------------------

          (b)  In addition to the Guaranteed Obligations, the Guarantor further
agrees to pay any and all reasonable costs and expenses (including reasonable
fees and disbursements of counsel) incurred by any Guaranteed Party in enforcing
any rights under this Guaranty together with any accrued but unpaid interest on
the Guaranteed Obligations (including, without limitation, interest which, but
for the filing of a petition of bankruptcy with respect to the Borrower, would
have accrued on the Guaranteed Obligations), which agreement shall survive
termination of this Guaranty.

          (c)  The Guarantor understands and confirms that the Guaranteed
Parties may enforce this Guaranty up to the full amount of the Guaranteed
Obligations against the Guarantor without proceeding against the Borrower or any
other Person, any security for the Guaranteed Obligations, or under any other
guaranty covering all or a portion of the Guaranteed Obligations.

          (d)  Notwithstanding anything in this Guaranty to the contrary, the
obligations of the Guarantor under this Guaranty shall be limited to a maximum
aggregate amount equal to the largest amount that would not render the
Guarantor's obligations hereunder subject to avoidance as a fraudulent transfer
or fraudulent conveyance under Section 548 of Title 11 of the United States Code
or any applicable provisions of comparable state law (collectively, the
"Fraudulent Transfer Laws"), in each case after giving effect to all other
 ------------------------
liabilities of the Guarantor, contingent or otherwise, that are relevant under
the Fraudulent Transfer Laws (specifically excluding, however, any liabilities
of the Guarantor in respect of intercompany Indebtedness to the Borrower or any
Subsidiary or Affiliate of the Borrower to the extent that such Indebtedness
would be discharged in an amount equal to the amount paid by the Guarantor
hereunder) and after giving effect as assets to the value (as determined under
the applicable provisions of the Fraudulent Transfer Laws) of any rights to
subrogation, reimbursement or contribution of the Guarantor pursuant to (i)
applicable law, or (ii) any agreement providing for

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rights of subrogation, reimbursement or contribution in favor of the Guarantor,
or for an equitable allocation among the Guarantor, the Borrower and/or any
other Person of obligations arising under guaranties by such Persons.

     2.   No Release.  The Guarantor agrees that the Guaranteed Obligations may
          ----------
be extended, renewed or otherwise modified, in whole or in part, without any
notice to or further assent from it, and that the Guarantor will remain bound by
this Guaranty notwithstanding any extension, renewal or other modification of
any Guaranteed Obligation.

     3.   Waiver of Notices.  The Guarantor waives notice of the acceptance of
          -----------------
this Guaranty, presentment, protest, notice, dishonor or default, demand for
payment and any other notices to which the Guarantor might otherwise be
entitled.

     4.   Obligations Absolute.  The obligations of the Guarantor under this
          --------------------
Guaranty are those of a primary obligor, and not merely a surety, are
independent of the obligations of the Guaranteed Parties, and shall not be
affected by any:

          (a)  change in the manner, place or terms of payment of (including the
currency thereof), and/or change or extension of the time of payment of, or
renewal or modification of, any of the Guaranteed Obligations, any security or
guarantee therefor, or any liability incurred directly or indirectly in respect
thereof; provided, that this Guaranty shall apply to the Guaranteed Obligations
as so changed, extended, renewed or modified;

          (b)  sale, exchange, release, surrender, realization upon, failure to
perfect any security interest in, or other alteration in any manner and in any
order of any property by whomsoever at any time pledged or mortgaged to secure,
or howsoever securing, the Guaranteed Obligations or any liabilities (including
any of those hereunder) incurred directly or indirectly in respect thereof or
hereof and for offset thereagainst;

          (c)  settlement or compromise of any of the Guaranteed Obligations,
any security or guarantee therefor or any liability (including any of those
hereunder) incurred directly or indirectly in respect thereof or hereof, or
subordination of the payment of all or any part thereof to the payment of any
liability (whether due or not) of the Borrower;

          (d)  actions or failures to act in any manner referred to in this
Guaranty which may deprive the Guarantor of its right to subrogation against the
Borrower to recover full indemnity for any payments made pursuant to this
Guaranty;

          (e)  failure of any Guaranteed Party to assert any claim or demand or
to enforce any right or remedy against the Borrower or any guarantor or any
successor thereto under the provisions of the Credit Agreement, any other Loan
Document or any other agreement or otherwise; or

          (f)  rescission, waiver, extension, renewal, amendment or modification
of any of the terms or provisions of the Credit Agreement, any other Loan
Document, any guarantee or any instrument or agreement executed pursuant
thereto.

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<PAGE>

     5.   Guaranty of Payment and Performance.  This Guaranty constitutes a
          -----------------------------------
guarantee of payment and performance when due and not of collection and the
Guarantor waives any right to require that any resort be had by any Guaranteed
Party to the Borrower, any other guarantor, any property by whomsoever at any
time pledged or mortgaged to secure, or howsoever securing, the Guaranteed
Obligations or any balance of any deposit account or credit on the books of any
Guaranteed Party in favor of the Borrower or any other Person.

     6.   Unenforceability of Obligations.  The obligations of the Guarantor
          -------------------------------
under this Guaranty shall not be subject to any reduction, limitation,
impairment or termination for any reason (other than by payment and performance
in full of the Guaranteed Obligations and termination of all Commitments under
the Credit Agreement, and except as limited in Section 1(d) of this Guaranty)
and shall not be subject to any defense or setoff, counterclaim, recoupment or
termination whatsoever by reason of the invalidity, illegality or
unenforceability of any of the Guaranteed Obligations, discharge of the Borrower
from any of the Guaranteed Obligations in a bankruptcy or similar proceeding or
otherwise (other than by payment and performance in full of the Guaranteed
Obligations and termination of all Commitments under the Credit Agreement, and
except as limited in Section 1(d) of this Guaranty).

     7.   Set-Off.  In addition to any rights now or hereafter granted under
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applicable law (including, without limitation, Section 151 of the New York
Debtor and Creditor Law) and not by way of limitation of any such rights, upon
the occurrence of any Event of Default, each Guaranteed Party is hereby
authorized at any time or from time to time, without notice to the Guarantor or
to any other Person, any such notice being expressly waived, to the extent
permitted by applicable law, to set off and to appropriate and apply any and all
deposits (general or special) and any other indebtedness at any time held or
owing by such Guaranteed Party to or for the credit or the account of the
Guarantor, against and on account of the obligations and liabilities of the
Guarantor to such Guaranteed Party under this Guaranty, irrespective of whether
or not such Guaranteed Party shall have made any demand hereunder and although
said obligations, liabilities, deposits or claims, or any of them, shall be
contingent or unmatured.

     8.   Reinstatement. This Guaranty shall continue to be effective and, if
          -------------
cancelled or otherwise terminated shall be reinstated, if at any time any
payment, or any part thereof, of principal of, interest on or any other amount
with respect to any Guaranteed Obligation is rescinded or must otherwise be
restored by any Guaranteed Party or any other Person upon the bankruptcy or
reorganization of the Borrower or any other Person or otherwise.   If claim is
ever made upon any Guaranteed Party for repayment or recovery of any amount or
amounts received in payment or on account of any of the Guaranteed Obligations
and any of the Guaranteed Parties repays all or part of said amount by reason of
(a) any judgment, decree or order of any court or administrative body having
jurisdiction over such Guaranteed Party or any of its property, or (b) any
settlement or compromise of any such claim effected by such Guaranteed Party
with any such claimant (including the Borrower), then and in such event the
Guarantor agrees that any such judgment, decree, order, settlement or compromise
shall be binding upon it, notwithstanding any revocation, termination or
cancellation hereof or of the Credit Agreement, any other Loan Document or any
other instrument evidencing any liability of the Borrower, and the Guarantor
shall be and remain liable to such Guaranteed Party hereunder for the amount so
repaid or recovered to the same extent as if such amount had never originally
been received by any such Guaranteed Party.

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<PAGE>

     9.   No Subrogation.  Notwithstanding any payment or payments by the
          --------------
Guarantor hereunder or any set-off or application of funds of the Guarantor by
any Guaranteed Party, the Guarantor shall not be entitled to be subrogated to
any of the rights of any Guaranteed Party against the Borrower or guarantee or
right of offset held by any Guaranteed Party of the payment of the Guaranteed
Obligations, nor shall the Guarantor seek to be entitled to seek any
reimbursement or contribution from the Borrower or any other guarantor in
respect of payments made by the Guarantor hereunder, until all amounts owing to
the Guaranteed Parties by the Borrower on account of the Guaranteed Obligations
are indefeasibly paid in full in cash.  If any amount shall be paid to the
Guarantor on account of the subrogation rights at any time when all of the
Guaranteed Obligations of the Borrower have not been indefeasibly paid in full
in cash, such amount shall be held by the Guarantor in trust for the Guaranteed
Parties, segregated from other funds of the Guarantor, and shall, immediately
upon receipt by the Guarantor, be turned over to the Administrative Agent in the
exact form received by the Guarantor (duly endorsed by the Guarantor to the
Administrative Agent, if required), to be applied against the Guaranteed
Obligations of the Borrower, whether matured or unmatured, in such order as the
Administrative Agent may determine.

     10.  Amendment and Waiver; Cumulative Remedies; Severability.  No
          -------------------------------------------------------
amendment, modification, termination or waiver of any provision of this
Guaranty, or consent to any departure by the Guarantor herefrom, shall be
effective without the written concurrence of the Majority Banks under the Credit
Agreement or as otherwise provided in the Credit Agreement including, without
limitation, Section 11.01(a) thereof.  No failure by the Guaranteed Parties to
exercise, and no delay in exercising, any right, remedy or power hereunder shall
operate as a waiver thereof; nor shall any single or partial exercise of any
right, remedy or power hereunder preclude any other or further exercise thereof
or the exercise of any other right.  No waiver of any breach or default under
this Guaranty shall be deemed a waiver of any other breach or default hereunder.
The remedies herein provided are cumulative and not exclusive of any remedies
provided by law or in equity.  The unenforceability or invalidity of any
provision of this Guaranty shall not affect the enforceability or validity of
any other provision herein.

     11.  Notices.  All notices, requests and other communications provided for
          -------
hereunder shall be in writing (including, unless the context expressly otherwise
provides, facsimile transmission) and mailed, transmitted by facsimile or
delivered, (a) if to the Guarantor, to the address or facsimile number specified
for notices on the applicable signature page hereof; (b) if to any Guaranteed
Party, to the notice address specified for such party on Schedule 1.01(A) to the
Credit Agreement; or (c) to such other address as shall be designated by any
party in a written notice to the other parties and the Administrative Agent.

     12.  Stay of Acceleration.  In the event that acceleration of the time for
          --------------------
payment of any of the Guaranteed Obligations is stayed, upon the insolvency,
bankruptcy or reorganization of the Borrower or any other Person, or otherwise,
all such amounts shall nonetheless be payable by the Guarantor immediately upon
demand by the Guaranteed Parties.

     13.  Representations and Warranties.  In order to induce the Banks to make
          ------------------------------
Loans and the Issuing Bank to issue Letters of Credit pursuant to the Credit
Agreement, and in order to induce the Interest Rate Guaranteed Parties to
execute, deliver and perform the Interest Rate Protection Agreements, the
Guarantor represents, warrants and covenants that:

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<PAGE>

          (a)  The Guarantor (i) is a duly organized and validly existing
corporation and is in good standing under the laws of the jurisdiction of its
organization, (ii) has the power and authority and all governmental licenses,
authorizations, consents and approvals to own or hold under lease its property
or assets, conduct its business and execute, deliver, and perform its
obligations under, this Guaranty and the other Loan Documents to which it is a
party, (iii) is duly qualified to do business as a foreign entity, and licensed
and in good standing, under the laws of each jurisdiction where its ownership,
lease or operation of property or the nature or conduct of its business requires
such qualification or license, except where the failure to so qualify would not
reasonably be expected to have a Material Adverse Effect and (iv) is in
compliance with all Requirements of Law, except to the extent that the failure
to do so could not reasonably be expected to have a Material Adverse Effect.

          (b)  This Guaranty and each other Loan Document to which the Guarantor
is a party constitutes the legal, valid and binding obligation of the Guarantor,
enforceable against the Guarantor in accordance with its terms, except as
enforceability may be limited by applicable bankruptcy, insolvency, or other
similar laws affecting creditors' rights generally and by equitable principles
of general application.

          (c)  The execution, delivery and performance by the Guarantor of this
Guaranty and each other Loan Document to which the Guarantor is a party have
been duly authorized by all necessary corporate action and do not and will not
(i) contravene any terms of the Charter Documents of the Guarantor, (ii)
conflict with or result in any breach or contravention of, or the creation of
any Lien (except under the Security Documents) under, any document evidencing
any material Contractual Obligation to which the Guarantor is a party of any
order, injunction, writ or decree of any Governmental Authority to which the
Guarantor or its property is subject, or (iii) violate any Requirement of Law.

          (d)  No approval, consent, exemption, authorization, or other action
by, or notice to, or filing with or approvals of any Governmental Authority is
necessary or required in connection with the execution, delivery or performance
by, or enforcement against (except as may be required by the Communications Act
of 1933, as amended, and the rules, regulations and policies of the FCC), the
Guarantor of this Guaranty and each other Loan Document to which the Guarantor
is a party.

          (e)  There are no actions, suits or proceedings, claims or disputes
pending, or to the best knowledge of the Guarantor, threatened at law, in
equity, or in arbitration before any Governmental Authority, against the
Guarantor or any of its properties or assets which (i) purport to affect or
pertain to this Guaranty or any other Loan Document to which the Guarantor is a
party, or any of the transactions contemplated hereby, or (ii) would reasonably
be expected to have a Material Adverse Effect.  No injunction, writ, temporary
restraining order or any order of any nature has been issued by any court or
other Governmental Authority purporting to enjoin or restrain the execution,
delivery or performance of this Guaranty, or directing that any other
transaction provided for herein not be consummated as herein provided.

     14.  Credit Agreement Covenants.  The Guarantor covenants and agrees that
          ---------------------------
on and after the date hereof and until the Aggregate Commitment and all Interest
Rate Protection Agreements have been terminated and no Loan or Letter of Credit
remains outstanding (other

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<PAGE>

than Letters of Credit, together with all fees that have accrued and will accrue
thereon through the stated termination date of such Letters of Credit, which
have been supported in a manner satisfactory to the Issuing Bank in its sole and
absolute discretion) and all Guaranteed Obligations have been paid in full
(other than indemnities described in Section 11.05 of the Credit Agreement and
analogous provisions in the Security Documents which are not then due and
payable), the Guarantor shall take, or will refrain from taking, as the case may
be, all actions that are necessary to be taken or not taken so that no violation
of any provision, covenant or agreement contained in Article VII or VIII of the
Credit Agreement, and so that no Default or Event of Default is caused by the
actions of the Guarantor or any of its Subsidiaries.

     15.  Successors and Assigns.  This Guaranty shall be binding upon the
          ----------------------
Guarantor and its successors and assigns and shall inure to the benefit of the
respective successors and assigns of the Guaranteed Parties and, in the event of
any transfer or assignment of rights by any Guaranteed Party, the rights and
privileges herein conferred upon that Guaranteed Party shall automatically
extend to and be vested in such transferee or assignee, all subject to the terms
and conditions hereof, provided, however, that the Guarantor may not assign any
of its rights or obligations hereunder without the consent of the Banks and any
such assignment without such consent shall be void.

     16.  Governing Law.  THIS GUARANTY SHALL BE DEEMED TO BE MADE UNDER, SHALL
          -------------
BE GOVERNED BY, AND SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS
OF THE STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAW.

     17.  Jurisdiction and Service. All judicial proceedings brought against the
          ------------------------
Guarantor with respect to this Guaranty may be brought in any state or federal
court of competent jurisdiction in the State of New York and by execution and
delivery of this Guaranty the Guarantor accepts for itself and in connection
with its properties, generally and unconditionally, the nonexclusive
jurisdiction of the aforesaid courts, and irrevocably agrees to be bound by any
judgment rendered thereby in connection with this Guaranty.  The Guarantor
irrevocably and unconditionally waives, to the fullest extent it may legally and
effectively do so, any objection which it may now or hereafter have to the
laying of venue of any suit, action or proceeding arising out of or relating to
this Guaranty in any state or federal court in the State of New York.  The
Guarantor irrevocably waives, to the fullest extent permitted by law, the
defense of an inconvenient forum to the maintenance of such action or proceeding
in any such court and irrevocably consents to service of process in the manner
provided for notices in Section 11.  Nothing in this Guaranty will affect the
right of any Guaranteed Party to serve process in any other manner permitted by
law.  If any agent appointed by the Guarantor refuses to accept service, the
Guarantor agrees that service upon it by mail shall constitute sufficient
notice.  Nothing herein shall affect the right of any Guaranteed Party to bring
proceedings against the Guarantor in the courts of any other jurisdiction.

     18.  Waiver of Jury Trial.  THE GUARANTOR HEREBY WAIVES, TO THE FULLEST
          --------------------
EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN
RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF, UNDER OR IN
CONNECTION WITH THIS GUARANTY, THE CREDIT AGREEMENT OR ANY OTHER LOAN DOCUMENT.
The Guarantor (a) certifies that no

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<PAGE>

representative, agent or attorney of any other party to the Loan Documents has
represented, expressly or otherwise, that such other party would not, in the
event of litigation, seek to enforce the foregoing waiver and (b) acknowledges
that the Banks and the other parties to the Loan Documents have been induced to
enter into the Loan Documents by, among other things, the foregoing waiver and
certification.

     19.  Release. This Guaranty is a continuing and irrevocable guaranty of all
          -------
Guaranteed Obligations now or hereafter existing and may be released only in
accordance with Section 11.01 of the Credit Agreement.

     20.  Counterparts.  This Guaranty may be executed in any number of
          ------------
counterparts, each of which when so executed and delivered shall be an original,
but all of which shall together constitute one and the same instrument.  A set
of counterparts originals executed by the Guarantor shall be delivered to the
Administrative Agent, and a copy thereof shall be furnished to the Borrower or
the Guarantor upon request therefor.

     21.  Security Documents.  The obligations of the Guarantor are secured by
          ------------------
certain of the Security Documents.  The Guarantor shall comply with all terms
and conditions of the Security Documents to which the Guarantor is a party, as
the same may be amended, restated, supplemented or otherwise modified from time
to time.


     [Remainder of page intentionally left blank; signature page follows]

                                       8
<PAGE>

     IN WITNESS WHEREOF, the undersigned has caused this Guaranty to be duly
executed as of the day and year first above written.

NEXSTAR FINANCE HOLDINGS, INC.

By: /s/ Perry Sook
    ------------------------
     Title: President

Address of Guarantor:

200 Abington Executive Park, Suite 201
Clarks Summit, Pennsylvania 18411
Attention: Perry Sook
Telephone: (570) 586-5400
Facsimile: (570) 586-8745

                      [Guaranty Agreement Signature Page]