I know some people have dogs and rabbits in the same household, but I would be very wary of letting them get together. Even if your dog, Cam, is gentle and playful normally, a rabbit may well bring out it's hunting instinct. Even if he doesn't mean to hurt the rabbit, he may well do so if he gets excited or over playful.
Also, even though your rabbit is in a pen, if Nuggett can see, hear, and smell your dog, it will probably be adding to making him timid and stressed in a new environment.
Hopefully, members who have rabbits and dogs will be able to give more info about whether you can safely keep them together.