1. Heat oven to 325°F. Generously grease 15x10x1-inch jelly-roll pan.
2. Stir butter into dry cake mix in large bowl with fork until mixture is completely blended and all of cake mix is moistened; sprinkle evenly into prepared pan. Press down firmly. Sprinkle chocolate chips, peanut butter chips, coconut and nuts in order, over crumb mixture. Drizzle sweetened condensed milk evenly over top.
3. Bake 30 to 35 minutes or until slightly bubbly and very lightly browned. Cool completely in pan on wire rack. Cut into bars. About 48 bars.