Company: SRV
Filing Date: 2025-11-17
Form Type: 424B2
Source: 0001398344-25-021029
Chunk: 48

Company: NXG Cushing Midstream Energy Fund
Filing Date: 2025-11-17
Form: 424B2
Chunk 48
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TERS</div>

Certain legal matters will be passed on by Skadden,
Arps, Slate, Meagher & Flom LLP, Chicago, Illinois, as special counsel to the Fund in connection with the Offer. Certain legal matters
will be passed on by Dechert, LLP, New York, New York, as special counsel to the Dealer Manager, in connection with the Offer.

<div align='center'>INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM</div>

Ernst & Young LLP, serves as the independent registered
public accounting firm of the Fund and will annually render an opinion on the financial statements of the Fund. Ernst & Young LLP
is located at 2323 Victory Avenue, Suite 2000, Dallas, Texas 75219.

| S-29 |

BASE PROSPECTUS

<div align='center'>$500,000,000

NXG Cushing Midstream Energy
Fund

Common Shares
Subscription Rights for Common Shares</div>

Investment Objective. NXG Cushing®
Midstream Energy Fund (the “Fund”) is a non-diversified, closed-end management investment company. The Fund’s investment
objective is to obtain a high after-tax total return from a combination of capital appreciation and current income.

Investment Strategy. The Fund seeks
to achieve its investment objective by investing, under normal market conditions, at least 80% of Managed Assets (as defined in this
Prospectus) in a portfolio of midstream energy investments (the “80% policy”). For purposes of the Fund’s 80% policy,
the Fund considers midstream energy investments to be investments that offer economic exposure to securities of midstream energy companies,
which are companies that provide midstream energy services, including the gathering, transporting, processing, fractionation, storing,
refining and distribution of natural resources, such as natural gas, natural gas liquids, crude oil refined petroleum products, biofuels,
carbon sequestration, solar, and wind. The Fund considers a company to be a midstream energy company if at least 50% of its assets, income,
sales or profits are committed to or derived from midstream energy services.

(continued on inside front cover)

The Fund has previously qualified, and intends
to continue to qualify, to be treated as a regulated investment company (“RIC”) under the Internal Revenue Code of 1986, as
amended (the “Code”). The Fund pursues its investment objective by generally investing in master limited partnerships (“MLPs”)
up to the