In a large bowl, measure Rice Chex cereal. Set aside.
In a medium saucepan over low heat, melt chocolate chips, peanut butter, butter, and vanilla extract; stir slowly and continuously until completely melted.
Remove melted mixture from heat and immediately pour over cereal; gently mix until cereal is coated.
Pour coated cereal into a gallon zip-top bag along with the powdered sugar; gently shake around until coated. Add in green and yellow M&M's candies; gently shake around until evenly dispersed.
Pour puppy chow onto a parchment/wax paper lined baking sheet to cool. Allow Green Bay Packers Puppy Chow to cool completely. Eat & Enjoy!
Notes
Green Bay Packers Puppy Chow should be stored in an airtight container and will keep 7+ days.