Preheat the oven to 275°F. Line a large baking sheet with parchment paper and spray with nonstick cooking spray. Add the cereals, pretzels, and cashews in a single layer.
Place the butter in a medium microwave-safe bowl, cover, and microwave on high to melt, about 1 minute. Add the brown sugar and maple syrup and whisk well until combined.
Pour the butter mixture over the cereal mixture and toss gently until evenly coated. Bake for 45 minutes, stirring halfway through. Cool completely on the sheet tray, stirring occasionally.
Add the peanut butter candies, candy corn, candy eyeballs and chocolate chips. Toss gently on the baking sheet.
Transfer to a serving bowl and ENJOY!!