In a microwave-safe dish, melt peanut butter, chocolate chips, and butterscotch chips in 30-second intervals stirring in-between each. Allow to cool for 5 minutes.
Mix in marshmallows to combine the chocolate peanut butter mixture. Combine until all marshmallows are mixed in.
Pour the chocolate marshmallow mixture into the prepare pan and spread evenly. Sprinkle with M&Ms.
Place the pan into the refrigerator to allow the mixture to set for one hour. Once chilled cut into squares to serve.
Notes
Nutritional values may vary and are meant to be a guide.