I don't wanna start a shit storm, but I think Canada got it right calling them first nations.
For one it's just more accurate, they're more than tribes, they're independent, sovereign, recognized nations, who were indeed here first. First nations, has a certain simplicity and forthrightness that's hard to fuck up.
Secondly, as a giant ass white dude from the Midwest I consider myself native. I hate to be rude about it, but my ancestors have been here for centuries, I'm not from anywhere else. I'm willing to bet Europe doesn't want me or any other American back.