Preheat oven to 350F. In an ungreased 8 or 9 inch square baking pan, combine Snack Cake Mix and cocoa powder. In a medium bow, combine water, egg, veg oil and vanilla. Beat with afork to blend. Stir into cocoa mixture until smooth and bleended. Sprinkle chocolate chips and nuts evenly over top of batter. Bake 35 to 45 minutes in preheated oven until surface springs back when touched with your fingers.