Microwave chocolate, milk and butter in medium microwavable bowl on High 1 to 1 1/2 minutes, stirring every 30 seconds. Stir until chocolate is completely melted. Spread evenly in crust. Refrigerate 30 minutes or until chocolate is firm. Arrange banana slices over chocolate.
Pour milk into large bowl. Add pudding mixes. Beat with wire whisk 1 minute. Let stand 1 minute. Gently stir in 1 1/2 cups of the whipped topping until smooth. Spoon over bananas in crust.
Refrigerate 4 hours or until set. Garnish with remaining whipped topping. Store leftover pie in refrigerator. Makes 8 servings.