In a bowl, beat cream cheese and sugar until smooth. Add whipped topping and mix well. Spread into crust.
In another bowl, beat milk and pudding mixes on low speed until combined; beat on high for 2 minutes. Let stand for 3 minutes. Stir in pumpkin and spices; mix well. Spread over cream cheese layer. Chill. Garnish with nuts and/or whipped topping if desired.
Graham cracker crust (9 inches): Combine 1-1/2 cups crushed graham cracker crumbs (24 squares), 1/4 sugar and 1/3 cup melted butter. Press onto the bottom and up the sides of an ungreased 9-in. pie plate. Bake at 375 until lightly browned, 8-10 minutes. Cool on a wire rack before filling.