there's a nip for this. i vibed a nostr chess game using it earlier this year if you want to check it out. i vibed it using older google models while checking out antigravity though so it kind of sucks, but at least you can see how i used nip-64.
https://github.com/SamSamskies/nostr-chess
https://github.com/nostr-protocol/nips/blob/master/64.md
