Munoz can pull off the UD. However, it would be an underwhelming and boring win. Mousasi has an active guard and he has no problem attacking from the bottom. If Munoz isn't able to pass his guard, he'll spend the round close to Mousasi's body, attempting to pass while peppering Moose with small shots to avoid the stand up. All the while he'll be defending the sub until Mousasi gets back up.
I was never a Mousasi believer. Yes, he has a ton of wins. Yes, he's well rounded. However, I felt he was seriously untested against he elite and never felt he deserved the praise he received on these boards. Still, he performed well against Machida. Better than I thought he would. The man will put a hurting on Munoz if he's too active.