Step 1Combine the chocolate chips, peanut butter and butter in a very large microwave-safe bowl. Microwave in 20-second increments, stirring between each, until just smooth. Alternatively, melt the chocolate chips, peanut butter and butter in a large, wide pot over low heat, stirring occasionally, until just smooth. Remove from the heat. Add the pretzels, peanuts and cereal and fold gently until evenly coated
Step 2Divide the powdered sugar between two gallon-sized resealable plastic bags, then divide the pretzel mixture between the bags. Seal the bags and shake until evenly coated. Transfer to a large bowl to serve as a snack mix, adding the peanut M&Ms if you’d like.
Nutty Buddy Clusters: Omit the butter and powdered sugar. At the end of step 1, drop the mixture by spoonfuls onto parchment-paper-lined baking sheets to form clusters. Sprinkle with flaky sea salt if desired. Refrigerate until firm, at least 10 minutes.