Pour 1/2 cup caramel topping into bottom of graham cracker crust. Sprinkle 1/2 cup chopped pecans over caramel layer.
Whisk pumpkin puree, cold milk, pudding mixes, cinnamon, and nutmeg together in a bowl until smooth; stir in 1 1/2 cups whipped topping. Spread pumpkin mixture over caramel and pecans in pie crust; top with remaining whipped topping. Refrigerate pie until chilled and set, about 1 hour. Sprinkle 2 tablespoons pecans over pie. Drizzle 2 tablespoons caramel topping over pie using a fork.