Preheat your oven to 350 degrees F and line a baking sheet with parchment paper or a silicone baking mat. Set aside.
In a large mixing bowl, combine Cheerios, Chex cereal, pretzels, and pecans.
Add in the melted butter, granulated sugar, brown sugar, cinnamon, and pumpkin pie spice. Mix until evenly coated.
Transfer to your lined baking sheet, spread into an even layer, then bake for 15 minutes.
While the snack mix cools, microwave white chocolate chips and vegetable oil in 30 second increments until smooth.
Drizzle the chocolate evenly over the snack mix, then let set completely (you can transfer to the fridge to speed this up) before breaking apart and enjoying!