Line a large baking sheet with a silicone baking mat or parchment paper. Set aside.
In a medium size microwave safe bowl, melt the pumpkin spice candy melts in the microwave on HIGH for 20 seconds. Stir the melts and heat again in 20 second increments until completely melted and smooth. Pour onto prepared baking sheet and spread out into a large rectangle. You're looking for about 1/4" thickness for your bark.
Melt the butterscotch chips in a separate small microwave safe bowl on HIGH for 20 seconds, stirring after each increment until completely melted and smooth. Dollop, drizzle, or pour the melted butterscotch chips evenly over the pumpkin spice rectangle. Use a knife, spatula, or a toothpick to swirl the two melted mixtures together.
Sprinkle with chopped nuts and festive sprinkles, pressing down lightly on the nuts to make sure they settle into the melted candy.
Allow the bark to set at room temperature in a cool, dry place. Mine usually takes about 1 hour. When completely cool, break into desired size pieces. Store bark in an airtight container at room temperature or the refrigerator up to 1 month.