In a microwave-safe bowl, combine chocolate chips, peanut butter, and coconut oil. Microwave in 20-second intervals, stirring after each, until smooth and melted.

Place 3 cups of Chex cereal in a large bowl. Pour half of the melted chocolate-peanut butter mixture over the Chex. Gently fold until coated.

Add the remaining Chex and pour the rest of the chocolate-peanut butter mixture over them. Fold until evenly coated, allowing some Chex pieces to stick together.

To coat the Chex with protein powder, either keep the mixture in the bowl or transfer it to a paper bag. Add ½ cup of protein powder, gently stir or shake until coated. Add the remaining protein powder and toss again until coated.

Allow the puppy chow to cool before storing it in an airtight container in a cool, dry place.