It is not because Nintendont is not an emulator. Just like Wine on Linux.
It uses the fact that the Wii's architecture is very close to GC and that the Wii could launch GC games natively. So it's pretty much just directing the system calls from a GC game to the Wii system.
As the Wii U literally has a Wii on board (vWii) it's working there too but it won't ever run on the Switch with a completely different CPU (ARM) and no way to run Wii or GC games natively.
I can only be proved wrong by porting Dolphin (which is a GC and Wii emulator) to the Switch just to run Nintendont from there which would be the most f*cking stupid thing to do as Dolphin already runs GC games.
However it's very likely that we'll see Dolphin on the Switch at some point either as a standalone emulator or as a RetroArch core so just stop dreaming of Nintendont on the Switch.