Im 100% sure that Cotto will win this fight. Cotto has more power, cotto has a better chin, Zab chin is not that hard, Cotto is very relaxed and doesnt get careless like Zab, and imo hes the better boxer. The only thing Zab gots going for him is his speed and more experiance in bigger fights.
I think Cotto will knock him out either in the first 3 rounds or in 8-10