Line two large rimmed cookie sheets with parchment paper or waxed paper.
In a large bowl, mix cereals, pretzel sticks (1 cup), half the M&M's, and until evenly mixed.
In a medium microwavable bowl, microwave candy (24 ounces) coating uncovered on High for 60 to 90 seconds, stirring after 1 minute, until almost melted. Continue to melt, as needed, using 30-second intervals, and stir vigorously until smooth. Add vanilla extract (1 teaspoon).
Gradually spoon the melted chocolate mixture over the cereal mix.
Top with the remaining M&M's and holiday sprinkles while the chocolate is still warm. All chocolate to set completely then break the mix up.