Line a 13x9-inch dish with half the graham crackers, breaking crackers to fit as needed.
Whisk milk and pudding mixes for 2 minutes. Let stand until soft-set, about 2 minutes. Fold in whipped topping. Spread evenly over crackers.
Top with remaining graham crackers.
In a microwave-safe bowl, microwave chocolate and butter until melted. Stir until blended. Stir in remaining ingredients. Spread over top. Refrigerate, covered, 8 hours or overnight.
