In a large bowl combine the pretzels, Cheerios, Corn Chex, peanuts (if using), M&M's and candy corn. Stir to combine then set aside.
In a microwave-safe bowl, heat white chips and oil on high for 60 seconds. Stir and microwave another 30 seconds and stir until completely melted and smooth.
Pour melted chocolate over cereal mixture and stir until it's all coated evenly in chocolate. Sprinkle the top with Halloween sprinkles (if desired.)
Serve in baggies or handfuls after chocolate has set.
Store leftovers in an airtight container for up to 3 days