Income earned on staking must be included in DIRPF and may or may not be subject to taxation. Normative Instruction RFB nº 1.888 art. 6.
Staking an NFT could be considered a taxable event depending on the circumstances. If the staking provider has control and disposal right of the staked NFT, or if the owner receives an item/coin/receipt in return for staking
the NFT, the event is most likely considered a taxable event.