I believe Natures Menu say you can cook the nuggets. Personally I would worry about feeding cooked bone, but i assume if it is finely ground it will be OK.
What else will he eat?
I really think he can't taste real food because of all the Bakers he is having, so if you can get him off the Bakers, even onto a stop-gap food, he should be more amenable to trying new things.
Have you tried a quality canned food? Or other quality wet foods? Most dogs love the taste and texture. How about ZiwiPeak? My dogs go loopy for it, it is much tastier than kibble.
Does he like plain raw meat? I tried the Natures Menu Country Hunter rabbit nuggets and my dogs were not impressed at all. There is a lot of veg in them and the meat isn't the best quality IMO. You could try some plain tripe (NM do blocks of it) most dogs find it irresistible