In a microwave-safe bowl, melt the chocolate wafers and mint candy together. Start with one minute, stir, and continue melting in 30-second intervals until smooth. This should take about 2 minutes total.

In a large mixing bowl, combine the Rice Chex cereal with the melted chocolate mixture. Use a large wooden spoon to fold gently until all the cereal is evenly coated.

In a large, gallon-sized resealable bag, add the powdered sugar. Carefully spoon the chocolate-coated cereal mixture into the bag. Seal the bag tightly and shake until the powdered sugar is coating all the cereal completely. Pour the coated cereal onto a large piece of wax paper and let the chocolate set, which should take about 20 minutes. Once set, combine the Mint M&Ms with the Chex mixture and store in an airtight container. Enjoy!