I actually think Duran could quite handily outbox JCC should he so choose, but don't see him adopting this style. If he fights in the pocket and tries to work JCC in close, it certainly plays more into Chavez' style than fighting someone like Whitaker. In these circumstances, I see it being very close.
Duran had that extra spark of brilliance/creativity on the inside both offensively and defensively that the mechanical Chavez just didn't have. He had a lot of very clever and subtle maneuvers on the inside that I feel would keep him one step ahead of Chavez throughout the fight.
At 135, it's one of the more attractive matchups in history. I think we know less about Chavez at 135 than any other weight class, because his time there as relatively brief, but it seems to have been a high point for him. Great body puncher, very tough, good boxer, exceptional ring general........he would give Duran a world of problems, but I see Duran escaping with a close decision, like 9-6 or 8-6-1. Very close.