Ridiculous thing to say.
Naz's problem was his balance was poor. Anyone who's ever been in a ring will know the difference between poor balance and a poor chin, no actually you don't even have to have been in ring, just watch and use some common sense.
Exactly. Naz would lean/sway away from punches in such a way that if he was even tapped the momentum would take him to the canvas because of the horrible balance. If anything, Naz's chin was good -- he was never knocked out and he NEVER looked as hurt as Khan looked against Limond.