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                                                                     Exhibit 4.2

                                                                  Execution Copy


      First Supplemental Indenture (this "Supplemental Indenture"), dated August
6, 2001 among Nexstar Finance Holdings, L.L.C., a Delaware limited liability
company ("Holdings LLC"), Nexstar Finance Holdings, Inc., a Delaware corporation
("Holdings Inc." and together with Holdings LLC, the "Issuers"), NBG, L.L.C., a
Delaware limited liability company ("NBG"), and The Bank of New York as
successor trustee to United States Trust Company of New York, as trustee under
the indenture referred to below (the "Trustee").

                              W I T N E S S E T H

      WHEREAS, the Issuers have heretofore executed and delivered to the Trustee
an indenture (the "Indenture"), dated as of May 17, 2001 providing for the
issuance of an aggregate principal amount of $36,988,000 aggregate principal
amount at maturity of 16% Senior Discount Notes due 2009 (the "Notes"); and

      WHEREAS, Section 4.19 of the Indenture requires the Reorganization to be
consummated by the Company and the Guarantor on or prior to November 30, 2001;
and

      WHEREAS, Section 5.01 of the Indenture permits the Reorganization to
occur; and

      WHEREAS, Section 10.5 permits the release of Nexstar Broadcasting Group,
L.L.C.'s guarantee of the Notes in connection with the consummation of the
Reorganization; and

      WHEREAS, Section 9.01(c) of the Indenture permits Holdings LLC, Holdings
Inc., NBG and the Trustee to enter into this Supplemental Indenture;

      WHEREAS, Section 5.02 of the Indenture allows for successor issuers and
provides that the former issuer shall be released from its responsibilities
under the Indenture if the transfer to the successor issuer complies with
Section 5.01 of the Indenture;

      WHEREAS, Holdings LLC and NBG have entered into an assignment and
assumption agreement dated as of August 3, 2001 (the "Assignment and Assumption
Agreement"), in order to effect the Reorganization; and

      WHEREAS, the Assignment and Assumption Agreement causes NBG to assume
responsibility for all obligations under the Indenture and the Notes and
relieves Holdings LLC of responsibility for all obligations under the Indenture
and the Notes.

      NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Issuers, NBG, and the Trustee mutually covenant and agree for the equal and
ratable benefit of the Holders of the Notes as follows:

      1.  Capitalized Terms.  Capitalized terms used herein without definition
shall have the meanings assigned to them in the Indenture.

      2.  modification of defined terms.  Section 1.01 of the Indenture is
hereby amended as follows:
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            a.  The definition of the term "Company" is hereby amended and
     restated in its entirety as follows:

           "Company" means NBG, L.L.C. and Nexstar Finance Holdings, Inc. and
           any and all of their respective successors.

            b.  The definition of the terms "Guarantor" is hereby amended and
     restated in its entirety as follows:

          "Guarantor" means any Subsidiary or other entity that executes a Note
          Guarantee in accordance with the provisions of this Indenture, and
          its respective successors and assigns.

            c.  The definition of the term "Nexstar" is hereby deleted from the
     Indenture.

     3.   Release of Holdings LLC. From and following the date of this
          Supplemental Indenture, Holdings LLC shall have no further
          responsibilities or obligations under the Indenture.

     4.   Release of Nexstar. From and following the date of this Supplemental
          Indenture, Nexstar Broadcasting Group, L.L.C.'s guarantee of the Notes
          shall be released.

          5.   Governing Law. THIS INDENTURE AND THE SECURITIES SHALL BE
GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK
BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE
EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE
REQUIRED THEREBY.

          6.   Counterparts. The parties to this Supplemental Indenture may sign
any number of copies of this Supplemental Indenture. Each signed copy shall be
an original, but all of them together represent the same agreement. One signed
copy is enough to prove this Supplemental Indenture.

          7.   Effect of Headings. The Section headings herein are for
convenience only and shall not affect the construction hereof.

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      IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed and attested, all as of the date first above
written.


                                 Nexstar Finance Holdings, L.L.C.

                                 By: /s/ Perry A. Sook
                                    ---------------------------------
                                 Name: Perry A. Sook
                                 Title: President and Chief Executive Officer

                                 Nexstar Finance Holdings, L.L.C.

                                 By: /s/ Perry A. Sook
                                    ---------------------------------
                                 Name: Perry A. Sook
                                 Title: President and Chief Executive Officer

                                 NBG, Inc.

                                 By: /s/ Perry A. Sook
                                    ---------------------------------
                                 Name: Perry A. Sook
                                 Title: President and Chief Executive Officer

                                 The Bank of New York as Successor Trustee to
                                 United States Trust Company of New York
                                  as Trustee

                                 By: /s/ Louis P. Young
                                    ---------------------------------
                                 Name: Louis P. Young
                                 Title:  Vice President

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