"Nuzzling" can mean to root or touch with the nose. In romance, it can mean just getting close and being snug. It doesn't necessarily have anything to do with the nose.
However, if I saw two people rubbing noses, I'd probably use "nuzzling". I can't think of a better word.
Like the Poles, we do have a phrase - "making like Eskimos".
You couldn't say "nosing" because that verb is used to describe looking uninvited into other peoples private affairs and has a negative feel to it.