There are plenty of great options in the old town itself. I would recommend using hotel.info they are a worldwide booking service with headquarters in Nürnberg, so you´ll probably get the hometown discount

We were there in late oct. Only tghere for one night so we weren't too picky. We opted for the Holiday Inn, Believe it or not. It was in the old town. Clean, one of the roomiest hotels we had in Europe. About a 3 min walk from the wall. 5 min to the marriage carousel fountain. The Castle is on the opposite side of the old town. So going there and back gives you the chance to see most of the old Nuremberg sites

There is the Hotel Astoria, close to the Opera house. You'll walk about 5-10 min. to the city and about 15 min. to the old town. There are pricier ones around that hotel, but I liked the small hotel atmosphere. :)