In a large bowl, mix together butter, peanut butter and powdered sugar until combined. Fold in the Reese's pieces. Roll the mixture into balls and set onto a plate.
Place the chocolate chips in the microwave and melt in 30-second intervals, stirring well until it is fully melted and smooth. Coat each peanut butter ball in the mixture and set onto a plate. Decorate with sprinkles. Let sit until it is completely set.