In a medium saucepan, combine light corn syrup, peanut butter, and sugar. Heat over medium heat, stirring constantly until smooth (do not let it boil).
Pour the mixture over the Corn Chex cereal in a large bowl. Gently fold the mixture until all cereal pieces are evenly coated.
Let the mixture cool slightly. Once cool enough to handle, form 2-tablespoon-sized clusters and place them on parchment paper.
In a separate bowl, melt milk chocolate chips and butterscotch chips together, either in the microwave or over a double boiler. Stir until smooth.
Spoon the melted chocolate-butterscotch mixture over each cluster.
Place the clusters in the freezer for 15-20 minutes to allow the chocolate to set before storing or serving.