As an individual investor, you can report your NFT gains to the IRS using Form 1040 (Income Tax Return) and Schedule D of this form for Capital Gains and Losses. Before filing it, use Form 8949 to reconcile your Sales and other Disposition of Capital Assets.
NFT creators are to report their income from NFTs according to their various filing statuses:
Self-employed creators are to use Schedule C and Schedule SE to report Profit or Loss From Business and Self Employment Tax, respectively.
C Corporations are to use Form 1120 for US Corporation Income Tax Return.
S Corporations are to file Form 1120S to report their US Income Tax Return for an S Corporation.
Partnerships are to use Form 1065 to report their US Return of Partnership Income.
To assist you in calculating your tax due and how to submit your report, use the additional information and tools on the IRS website.