This is not an easy decision for the government of Mexico. On the one hand, it looks really bad if it appears that they want to extradite Guzman because no prison in Mexico can hold him and they have to turn to the "gringos" to bring him to justice. On the other hand, another escape would be an even bigger humiliation.
Narco traffickers in Mexico have a certain "Robin Hood" image among many people. And those people will resent the U.S. getting involve in their countries business.