In medium bowl, combine flour, nuts and butter; mix thoroughly and press into the bottom of a greased 9x13-inch baking dish. Bake at 350 degrees 20 minutes. Cool on wire rack.
In medium bowl, with electric mixer; combine cream cheese, confectioner's sugar and one carton of the dessert topping. Beat until well combined and spread over cooled cake layer in dish. Refrigerate.
In large bowl with electric mixer, combine milk and chocolate pudding mixer; beat three minutes at low speed until thickened and glossy. Spread evenly over cream cheese layer in dish. Refrigerate until pudding is set.
Spread remaining carton of dessert topping (like Cool Whip) evenly over chocolate layer and refrigerate until serving time.