can say a khajiit wear nord armor?

Yes. "Nord Armor" is just armor made in the Nord style. So if it's Iron Armor, it can be any racial style which will make it look different but will functionally be the exact same.

Forgive me if this isn't public information. It's hard to keep track of what's known and what isn't. I do think I've read as much in a dev interview, though..

thanks