Prepare the cereal
Place the Chex cereal in a large mixing bowl and set aside.
Melt the chocolate mixture
In a microwave-safe bowl, combine semi-sweet chocolate chips, peanut butter, and butter.
Microwave in 30-second intervals, stirring after each, until melted and smooth.
Stir in the vanilla extract.
Coat the cereal
Pour the melted chocolate mixture over the cereal.
Gently stir with a spatula until all pieces are evenly coated.
Add powdered sugar
Transfer the coated cereal to a large zip-top bag or container with a tight-fitting lid.
Add the powdered sugar, seal, and shake until fully coated.
Add holiday extras
Spread the coated cereal onto a baking sheet lined with parchment paper.
Sprinkle with M&M’s, pretzels, and sprinkles while still slightly sticky.
If desired, drizzle with melted white chocolate for extra holiday flair.
Cool & serve
Let the mix cool completely before serving or storing.