None of these APIs is native to NT, they're
implemented on top of it.
I think only at boot you can run code that uses the NT API directly.
Amusingly, I
have a device in my airplane that runs NT4 without any Windows
graphical API on it. You can see the thing printing the NT4 startup and
build number when you power it on and it will BSOD.
I actually worked with the n10 and i860. IBM build a 4 processor i860
card. We ported the 370/386 AIX to it.
The only non x86 chip I worked with NT on was the iTanium (or as we called
it the iTanic). I might have had an NT Alpha around but we pretty much
were an OSF/1 shop at the time.