Does Nintendo allow ROM hacks?

Does Nintendo allow ROM hacks? The majority of ROM hacking is done on NES and SNES games (including Sega Mega Drive/Genesis games to an extent), since such games are small and simple compared to games of more advanced consoles such as the Nintendo 64 or Nintendo DS.

The majority of ROM hacking is done on NES and SNES games (including Sega Mega Drive/Genesis games to an extent), since such games are small and simple compared to games of more advanced consoles such as the Nintendo 64 or Nintendo DS.