Peanut Butter Rocky Road Squares

6 ounces semisweet chocolate chips
1/2 cup peanut butter
1/2 cup salted peanuts
6 ounces butterscotch chips
3 cups miniature marshmallows

Place chocolate chips, butterscotch chips, and peanut butter in microwave-safe bowl. Microwave uncovered on HIGH until softened, 2 to 2 1/2 minutes. Stir until melted and smooth. Mix in marshmallows and peanuts until evenly coated. Spread in buttered 8-inch square pan. Refrigerate until firm. Cut into squares.