Combine chocolate chips, peanut butter, and butter in a microwave-safe bowl. Microwave in 30-second bursts, stirring after each, until smooth and fully melted (about 1½-2 minutes total). Stir in vanilla extract and salt until blended.
1 cup semi-sweet chocolate chips, 0.5 cup peanut butter, 0.25 cup butter, 1 teaspoon vanilla extract, 0.125 teaspoon salt
Let the melted chocolate mixture sit for 1-2 minutes to cool slightly; this prevents making the cereal soggy when combined.
Pour the chocolate mixture over 9 cups of Rice Chex in a large bowl. Stir gently with a spatula, folding from the bottom up, until every piece is coated without crushing the cereal.
9 cups Rice Chex cereal
Transfer the coated cereal to a large sealable plastic bag or container. Add 1½ cups powdered sugar, seal, and shake gently in bursts of 10 seconds on, pause, then 10 seconds on until all pieces are evenly coated.
1.5 cups powdered sugar
Spread the coated cereal on parchment paper or a clean baking sheet and let sit for 10-15 minutes until the chocolate sets completely. Break apart any clumps before serving.
