Start by crushing the Nutter Butter cookies into fine crumbs. You can use a food processor or place them in a sealed plastic bag and crush them with a rolling pin.
In a mixing bowl, combine the crushed Nutter Butter cookies with the melted butter. Press this mixture into the bottom of a greased 9x9-inch baking dish to form the crust.
In another bowl, mix together the creamy peanut butter and powdered sugar until it forms a smooth and creamy mixture.
Spread the peanut butter mixture evenly over the Nutter Butter crust in the baking dish.
In a microwave-safe bowl, melt the semi-sweet chocolate chips in 30-second intervals, stirring in between until smooth.
Pour the melted chocolate over the peanut butter layer and spread it out evenly.
Place the dish in the refrigerator and let it chill for at least 2 hours, or until the chocolate is set.