Lightly butter a 9×13-inch baking pan and set aside.
In a medium saucepan over medium heat, combine sugar and corn syrup. Stir until it just begins to boil.
Remove from heat, stir in peanut butter until smooth and well blended.
Pour mixture over Rice Krispies in a large bowl. Gently fold until cereal is evenly coated.
Transfer mixture to prepared pan. Press firmly with a spatula to ensure an even layer.
In a microwave-safe bowl, melt chocolate and butterscotch chips in 30-second intervals, stirring between each, until smooth.
Pour melted topping over cereal layer and spread evenly.
Allow Scotcharoos to cool at room temperature until set, about 30 minutes.
Use a sharp knife to cut into 24 bars. Enjoy!