COAT 13 x 9-inch baking pan with cooking spray.
COMBINE peanut butter, sugar and corn syrup in large saucepan. Cook over medium-low heat, stirring frequently, until melted. Remove from heat. Add cereal; stir until thoroughly coated. Press onto bottom of prepared baking pan.
MICROWAVE butterscotch morsels and semi-sweet chocolate morsels in large, uncovered, microwave-safe bowl on HIGH (100%) power for 1 minute; STIR. Morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until smooth. Spread over cereal mixture.
REFRIGERATE for 15 to 20 minutes or until topping is firm. Cut into bars.