Probably an ok stoppage given how the previous minute or so went but do feel like the ref should have warned Chris he was close to stepping in beforehand.
Those final few shots weren't really anything special and Chris was still with it and defending/blocking.
I don't think Chris would have brought it back in the third but there were a few seconds left and he was in a bad position but defending and still with it. Ask to see more from him, warn him you're going to step in if he can't improve his situation etc but despite thinking he wasn't going to turn it around it didn't seem like those last few seconds were a fight ending situation with the round seconds from ending.
That said I don't think The Chris should fight again - he could probably pick up a win against bottom of the barrel MW but he's a former champion who hasn't been able to hang with the top 20 for a good few years and is now liable to getting finished by those knocking on the door of top 50. You ended Anderson Silvas reign, don't end up being some fella getting sparked out on prelims of a UFC Fight Night Event in front of a couple of hundred people crowd by some fella making his name off of you.