If you'll remember, when Chris Nolan was initially going to do Batman Begins. He called up Hans and asked him if he would want to do it. It was Hans who suggested that he and James Newton Howard collaborate on the score. So I think it would definitely be Hans, hence Inception. lol
They are both great composers, but I would go with Zimmer.
Christopher Nolan isn´t the director the academy need, but he is the one the world deserves right now. And so they´ll ignore him, but he can take it. Because he is not an oscar winner. He is a silent moviemaker, a watchful screenwriter, A GREAT DIRECTOR.