Cut the chicken meat finely. Boil the macaroni according to package directions and drain it. Add the butter.
Put half the macaroni in a buttered oven dish and cover with the chicken meat that's been seasoned with salt and black pepper. Add the remaining macaroni. Mix half of the parmesan with the cream, season with the nutmeg, some salt and black pepper.
Cover the dish with the remaining parmesan. Bake in a moderate preheated oven.