Line a large baking sheet with parchment paper. Spread kettle corn, pretzels, Chocolate Chex, candy corn, marshmallows, chopped candy bars, and Oreos evenly across the pan.
Drizzle the melted white chocolate over the top, then gently toss with a spatula until everything is lightly coated.
While still wet, scatter gummy worms and Halloween sprinkles over the mix so they stick.
Let the mix sit at room temperature (or chill briefly in the fridge) until the chocolate sets.