Measure out the Chex cereal into a large bowl, set aside.
Measure out the powdered sugar in a large plastic bag, set aside.
In a large saucepan melt the chocolate chips (milk, semi-sweet or dark - your preference), peanut butter and butter together over low heat.
After everything is melted together and very smooth add the vanilla - mix well.
Pour the melted chocolate mixture over the Chex. Stir together well, making sure that all the pieces of Chex are covered in the melted chocolate.
Pour the Chex mixture into the plastic bag with powdered sugar in it. Close bag & shake well until all the Chex pieces are coated in a layer of powdered sugar (can use more powdered sugar if you like).