Crush 16 oreo cookies until coarse. Add the melted butter and press into the bottom of a 9x9 inch pan.
In a large bowl, beat the cream cheese, peanut butter and 1 cup powdered sugar until smooth. Fold in half of the whipped topping and spread over the oreo crust layer. Sprinkle with the chopped peanut butter cups but reserving some to sprinkle on the top.
In another bowl, beat the milk, pudding mix, and remaining 1/2 cup powdered sugar on low for about 2 minutes. Let stand for two minutes. Fold in the remaining whipped topping. Spread on top of the peanut butter cups. Sprinkle the top with remaining crushed oreos and peanut butter cups. Cover and chill for 3 hours before serving.