Not exactly a PB pie, but still good and quick:
1 chocolate cookie pie crust
3 full size Butterfinger candy bars, frozen
1 tub of whipped topping (Cool Whip)
Using a hammer or heavy object, crush frozen Butterfingers into small pieces while still in the wrapper. Fold crushed pieces into whipped topping, stirring until well blended. Place in pie crust and refrigerate over night.