In a small bowl, combine coconut and butter.
Press onto the bottom and up the sides of a greased 9-in. pie plate. Refrigerate for at least 30 minutes or until firm.
In a small bowl, whisk milk and pudding mixes for 2 minutes.
Let stand for 2 minutes or until soft-set. Spread 1-1/2 cups over crust.
Fold whipped topping into remaining pudding; spread over pie.
Sprinkle with pistachios if desired. Cover and refrigerate for at least 2 hours.