I attempted this a while ago, running the Switch OS (Horizon/NX) on a Jetson TX1. It's definitely possible, *but* it requires modifications to the OS services, otherwise you'll just fry the Jetson (that was a lesson learned the hard way...). The pinmuxing between the two devices is different, so you'd need to modify that at least. And then you'd probably need some more modifications to get joycons to work (how do you sync them without a rail), etc...
The kernel however runs absolutely fine with zero modifications required. HorizonOS is a microkernel, and all the components are fairly well separated. To make it work on a jetson, you'd only have to replace a handful of services to make it work.
> IANAL, but in the US at least, I think every person would need to buy their own Switch and dump the software themselves for it to be even remotely legal.
Honestly, I'm pretty sure it'd violate the DMCA DRM protections in the US (you'd have to dump some crypto keys and provide them to an EL3 reimplementation, like Exosphere, to run anything below the kernel).