I am using web3 sdk of Solana to query balances or make transactions. Now I would like to know if it's possible to achieve one of the following actions:
Absolutely, to answer your questions:
getTokenAccountsByOwner
, where the owner is the wallet address: https://solana-labs.github.io/solana-web3.js/classes/Connection.html#getTokenAccountsByOwnergetTokenLargestAccounts
will give the holders for the nft: https://solana-labs.github.io/solana-web3.js/classes/Connection.html#getTokenLargestAccounts