PREHEAT oven to 350° F. Grease 13 x 9-inch baking pan.
COMBINE 3 cups cake mix, eggs, pumpkin pie mix and pumpkin pie spice in large mixer bowl. Beat on low speed until moistened. Beat on medium speed for 2 minutes. Pour into prepared pan.
COMBINE remaining cake mix, coconut and nuts in small bowl. Cut in butter with pastry blender or two knives until mixture is crumbly. Sprinkle over batter.
BAKE for 30 to 35 minutes or until wooden pick inserted in center comes out clean. Cool in pan on wire rack.