In small large bowl, combine the cake mix, 1 egg, butter and 2 tsp. pumpkin pie spice until crumbly. Press into a 13x9-in. baking dish; set aside. , In a large bowl, beat cream cheese until smooth. Add remaining 2 eggs; beat on low speed just until combined. Stir in the pumpkin, milk, cinnamon, salt and remaining 2 tsp. pie spice. Pour into crust; sprinkle with nuts. Place pan on a baking sheet. , Bake at 350° for 35-45 minutes or until set. Cool. Refrigerate until serving. Cut into squares; garnish with whipped cream if desired.