As long as the game can be played on windows/pc either in browser or with a download youre good to do whatever :) !
There are web-native emulators for numerous retro consoles, including the NES. :) Maybe you can make your NES ROM playable on Itch by following this guide: https://www.matthughson.com/2020/07/17/nesdev-embedding-an-emulator-on-itch-io/