In a large microwave-safe bowl, add nutella, chocolate chips, and butter. Microwave the chocolate mixture for 30-second intervals, stirring each time, until all the chocolate chips are melted.

Add the Rice chex cereal to the chocolate mixture.

Gently stir the cereal into the chocolate. Move fast because once the chocolate mixture starts to cool, it is harder to stir into the cereal mixture. Once the chocolate is coating the Rice Chex, add the powdered sugar.

Add the cover, make sure it is tight, and shake the bowl. Shake for a solid thirty seconds, and then remove the cover. If you get a powdered sugar cloud, give the puppy chow a good stir and shake it again. Keep doing this until the powder sugar is combined. If your bowl has no cover, use a large zip-top bag and break it into two batches.

Allow puppy chow to cool on a parchment paper covered baking sheet.

Store it in an airtight container on the countertop.