Just a general inquiry, is one allowed to play an SNES or NES game on the Nintendo Switch as they have emulators for the device and have it be valid or is this banned?

Most of the NES/SNES games available on the Switch have it listed as a platform, and the mods can add it if it’s not there. So, yes, it’s a valid platform. I wouldn’t recommend it however as it will run slower than an actual console or an actual emulator, so if possible I would recommend one of those if you plan on taking a game very seriously.