Line two trays with parchment. Put the butterscotch chips and peanut butter in a microwave-safe bowl.
Microwave at 50% power in 30-second bursts, stirring thoroughly after each, for 2 to 3 minutes total until smooth. Stop heating as soon as the last chips melt.
Fold in the chow mein noodles and peanuts gently until coated, keeping most noodles intact.
Use two spoons to drop 24 small clusters onto the lined trays, leaving space around each.
Let set at cool room temperature for about 1 hour, or refrigerate for 20 minutes, before lifting from the parchment and packing.