MICROWAVE chocolate morsels, butterscotch morsels and peanut butter in large, uncovered, microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; STIR. The morsels may retain some of their original shape. If necessary, microwave at additional 10 to 15-second intervals, stirring just until morsels are melted. Whisk in evaporated milk. Stir in nuts. Serve warm over ice cream or cake. Store remaining sauce tightly covered in refrigerator.
Recipe makes 4 1/2 cups.