In a large skillet scramble the eggs with the parsley and nutmeg. In a 9 inch square baking dish layer the scrambled eggs, salt and pepper to taste, sour cream, green onions, bacon pieces, mushrooms, and cheddar cheese. Refrigerate the casserole overnight. Bake in a 300 oven for 20 to 30 minutes, until the cheese is melted. Do not overbake.