Preheat oven to 325º. In a medium bowl, combine flour, margarine, and 2/3 cup chopped walnuts until well mixed. Press mixture into 9x13" baking pan. Bake for 25 minutes until lightly browned. Be sure to watch closely so it does not get too brown. Allow crust to cool
Beat softened cream cheese until smooth. Add powdered sugar and half of whipped topping; spread mixture over baked and cooled crust.
Mix pudding with milk; pour over cream cheese layer. Top with remaining whipped topping; sprinkle with nuts to garnish.