Ah, much better idea! Some medium crystal would be a good idea, I normally wouldn't use a couple of pounds, but if you want it sweetness and caramel it wouldn't be a bad idea. For chocolate I've had the best luck with cocoa powder (mix it with some hot water and add it to secondary), although some chocolate malt for color/complexity wouldn't be a bad idea either. For the nuts I think extract is probably the way to go. Keep the hops light so they stay out of the way.