Same here. Norton's top-level boxing ability combined with his considerable size/strength advantages would be a bit too much to overcome for Norris.
Boxers do quite well in MMA competitions once they learn the fundamentals of wrestling and a few submission holds. It'll be interesting to see if Floyd Mayweather Jr. backs up all the smack he's been talking and steps into the MMA ring.
OTOH, the same is true for a lot of martial arts fighters. My brother ran a dojo back when Lee, Norris, Alan Steen, and some of the other guys were on the scene. The guy I met that scared me the cr!p out of me was a little Korean guy named Yamashita. Rumor was that he was big in the South Korean mafia as a "problem solver" and solved one of the wrong problems and had to clear out to the US to keep from getting solved himself, if you get my drift. He never made these claims, but it was talked about a lot around him, although not in front of him. I have no idea if it was true or not. I only met him at tournaments, and he was extremely polite and formal. I saw him get mad, once. He did short sword and long sword demos, and could do stuff like toss an orange into the air and cut it in half, then quarter it before the orange separated from the first cut, really amazing stuff. Anyway, a couple of fighters were talking and laughing about something else close to where he was practicing, and he thought they were laughing at him. He turned on them with the sword still in his hands and said, "You laugh at Yamashita? I cut out your guts." He spoke in a low voice, but you had to see his face. He was about 5' 1." I've been around some fairly rough stuff, and this guy scared me to death, and he wasn't even talking to me. The other guys, who were darned tough tournament fighters, apologized in a very panicked way.
There are actors, sportsmen, and the real thing. Stallone is an actor.