Divide the Chex cereal evenly into two large bowls (about 5 1/2 cups of cereal in each bowl). Line two baking sheets with parchment paper or wax paper.

In a small microwave-safe bowl, combine the chocolate chips, peanut butter, and butter. Microwave on high power in 30-second increments, stopping to stir. Stop as soon as you can stir the mixture until it is smooth - this should only take 1 to 2 minutes total. Stir in the vanilla.

Pour the melted chocolate mixture over the Chex in one of the bowls. Stir gently until the cereal is evenly coated.

Transfer the mixture into a gallon-sized Ziploc bag, then add 1 1/2 cups of powdered sugar. Shake gently until the cereal is completely coated. Pour out onto one of the lined baking sheets. Let it sit for about 10 minutes or until the chocolate is set.

In a small microwave-safe bowl, microwave the red candy melts in 30-second intervals, stirring vigorously after each increment until the melts are completely smooth - this only takes 1 to 2 minutes.

Pour the candy melt mixture over the remaining bowl of Chex and stir gently until it's evenly coated.

Transfer the mixture into a gallon-sized Ziploc bag, then add 1/2 cup of powdered sugar and a few tablespoons of Valentine Sprinkles. Shake gently until evenly coated. Pour out onto the remaining lined baking sheet. Let it rest for about 10 minutes.

When the Chex mix is no longer sticky to touch, and the chocolate has set, toss the two mixtures together and add in the Valentine M&M's. Enjoy immediately, or store in an airtight container.