I really dont think so. you may be underrating chisora's chin:huh. remember, even though he did get KO'd by haye, before that he had taken flush bombs from tremendous punchers man. if this fight were to ever happen and chisora's punch resistance hasn't faded, mitchell is the one with the flimsier chin and it would definitely be a fight of "who hits who first." who's chin would you rely upon to crack first?