Add the Chex to a medium-sized mixing bowl.
In a separate, microwave-safe bowl, melt the chocolate in 30-second intervals in the microwave, stirring in between until fully liquid.
Stir in the peanut butter until fully incorporated.
Drizzle the chocolate mixture over the Chex a bit at a time, stirring lightly in between to evenly coat each piece before adding the next coat. Repeat until the chocolate mixture is completely used up and the cereal is thoroughly and evenly coated.
Scoop the coated cereal into a gallon-sized resealable bag and top with powdered sugar. Seal the bag and shake it back and forth to evenly distribute the powdered sugar throughout the bag.
Line a baking sheet with parchment paper and pour the freshly-dusted cereal out onto the tray. Apply more powdered sugar to any bare spots and toss to coat. Add in the desired amount of pretzels and M&Ms, and toss to evenly distribute.
Serve either directly from the tray or scoop into holiday tins for a party or to make great gifts!
