Prepare a large baking sheet by lining it with parchment paper to prevent sticking.

Place the butterscotch chips and peanut butter in a medium microwave-safe bowl. Microwave in 30-second intervals, stirring well after each, until the mixture is completely smooth and melted.

Add the chow mein noodles to the bowl and stir gently until all the noodles are evenly coated in the butterscotch-peanut butter mixture.

Using a 2-tablespoon cookie scoop (or a spoon), portion the mixture onto the prepared baking sheet, leaving a little space between each cookie.

Press a few mini M&Ms on top of each cookie and finish with a light sprinkle of Christmas sprinkles.

Let the cookies sit at room temperature for about 1 hour to firm up, or place the tray in the refrigerator for 20 minutes if you want them to set more quickly.