Does JMM have a good chin?

No, the fact he goes down so much shows he has a bad chin. He just has ridiculous recovery powers.

Horrible chin, near perfect recovery & heart. But he's getting ko'd this time for sure.

He's a notoriously slow starter and prone to the odd flash knockdown. But there's no chance of knocking him out, he just gets caught cold sometimes.

He has never been knocked out or stopped though, and while he is a good boxer he ain't a defensive genius although he does tend to improve on that as fights go on. That has to count for something.