In a large saucepan, melt the butter, chocolate chips, and peanut butter over low heat, stirring until smooth.
Remove from heat and stir in the vanilla extract.
In a large bowl, add the Rice Chex cereal.
Pour the melted chocolate mixture over the cereal.
Gently stir until all pieces are evenly coated.
Place the powdered sugar in a large zip-top bag.
Add the coated cereal to the bag and seal it.
Shake the bag until the cereal is well coated with powdered sugar.
Spread the mixture onto a baking sheet lined with parchment paper to cool.
Once cooled, serve and enjoy!