Prepare two large baking sheets by lining them with parchment paper or silicone mats. Set aside.
In a large mixing bowl, combine the corn cereal, rice cereal, oat cereal, pretzels, and peanuts, mixing well to distribute evenly.
Melt the white chocolate in a microwave-safe bowl, heating it in 30-second intervals at medium power, stirring frequently until smooth and fully melted. Be careful not to overheat.
Drizzle the melted chocolate over the cereal mixture, then gently fold everything together until all ingredients are well coated.
Quickly stir in the holiday chocolate candies, then spread the mixture onto the prepared baking sheets in an even layer. Sprinkle the top with festive sprinkles if desired.
Allow the mix to set at room temperature for about 20 minutes, or place it in the refrigerator for a quicker setting time. Once firm, break into clusters and serve.