Sure, but the real problem with N64 isn't quantity but the way controller emulation is always terrible.
NES is fine. You just need directional input and two other buttons. Whatever two face buttons are most comfortable for you is fine - A and B or Y and B or X and A or whatever. Likewise for Game Boy.
SNES is also fine. You just need directional input, four face buttons, and two shoulder buttons.
GBA is like SNES but with two fewer face buttons. Easy.
GameCube just needs two sticks, d-pad, four face buttons, and at least three shoulder buttons. People like to talk about pressure sensitivity but most games don't rely on it; the ones that do ought to be ported anyway rather than emulated.
DS, 3DS, Wii, and Wii U are where it really gets tricky. But honestly I don't expect any of these systems to have Virtual Console support on Switch anyway.
N64 is in a weird basket where most of its face buttons end up having to be remapped. And it's also the home for a ton of 3D Nintendo games that don't support analog camera controls. And its graphics are super dated but not quite in the way that makes them retro and appealing like NES, SNES, Game Boy, and GBA games. Please remaster all of them so none of this is ever a thing anyone has to deal with on Switch.