Measure out 9 cups of Chex cereal and place in a large bowl.
In a microwave-safe bowl, combine chocolate chips, peanut butter, and butter.
Microwave in 30-second intervals, stirring until smooth.
Stir in vanilla extract once melted.
Pour the chocolate mixture over the Chex cereal and stir to coat.
Transfer coated cereal into a zip-top bag with powdered sugar.
Seal the bag and shake until the cereal is coated.
Spread onto a baking sheet lined with parchment paper to cool.
Once cooled, enjoy immediately or store for later.