In a large bowl, mix together butter and powdered sugar until smooth. Add in the powdered sugar and mix until it is fully combined. Fold in the sprinkles.
Press the mixture into a baking dish. Place the chocolate chips into a microwave-safe bowl, and heat in the microwave in 30-second intervals, stirring well until it is fully melted and smooth.
Spread the chocolate evenly over the peanut butter mixture. Let sit until it is completely set. Cut into bars.