Combine ground beef, egg, Rice Krispies, salt, pepper and onion. Mix well. Mix together sugar, catsup, nutmeg and mustard. Add 1/2 of this sauce to ground beef mixture. Mix well. Put meat loaf into a pan. Pour remaining sauce over loaf and add a little water around sides of pan. Bake at 325 degrees for 1 hour or 1 1/2 hours.