Melt margarine. Add flour and nuts. Mix and press in a Pyrex dish. Bake at 350°F for 20 to 25 minutes. Let cool completely.
Mix 1 cup powdered sugar, 8 oz cream cheese, and 1 cup Cool Whip together and spread on crust after it has cooled.
Cook one large package of pie filling (preferably chocolate) according to package directions. Let cool then spread over pie.
Spread Cool Whip over top of pie. Grate one Hershey bar and sprinkle on pie. Refrigerate before serving.