Place both the butterscotch chips and the chocolate chips in a large microwave-safe bowl. Melt the chips together in the microwave, stirring chips every 30-45 seconds, until smooth. Remove from microwave and begin folding in the chow mein noodles a little at a time until they are completely coated with the melted chip mixture. Fold in peanuts until they are completely coated. Drop chow mein mixture by the spoonful onto prepared baking sheet. Place baking sheet in the refrigerator until Chow Mein Cookies have completely set. Once Chow Mein Cookies have set, store covered at room temperature.