Re: ROMs on nintendont

nkit.iso is fine but you have to rename it to .iso

"I was born in the right generation"

Here is the official list of accepted formats: https://github.com/FIX94/Nintendont (that's also the source code for Nintendont, so it is better to download it from the release page to get the latest version). If you have the storage space, I would just recommend to use the full ISO image since they aren't too big.