Gather all ingredients and equipment to streamline your process.

In a microwave-safe bowl, combine the chocolate chips and peanut butter. Microwave in 30-second intervals, stirring between each interval, until smooth and fully melted.

Stir in the vanilla extract until well combined.

Place the Rice Chex cereal in a large mixing bowl. Pour the melted chocolate mixture over the cereal and gently stir until every piece is evenly coated.

Sprinkle the powdered sugar over the coated cereal. Toss gently to ensure each piece is covered without breaking the cereal.

Line a baking sheet with parchment paper if desired, and spread the Puppy Chow mixture in an even layer to cool.

Allow the mixture to cool completely at room temperature so the coating can harden properly.

Break the Puppy Chow into pieces and serve immediately or store in an airtight container.