Reserve 1/3 cup chopped pretzels. In a large microwave-safe bowl, microwave 6 tablespoons butter on high for 45-60 seconds or until melted. Stir in marshmallows; cook 1 to 1-1/2 minutes or until marshmallows are melted, stirring every 30 seconds. Stir in Rice Krispies and remaining chopped pretzels. Immediately press into a greased 13x9-in. baking pan., In another microwave-safe bowl, combine 2 tablespoons butter and 1/4 cup corn syrup. Microwave, uncovered, on high for 45-60 seconds or until butter is melted, stirring once. Add peanut butter chips; cook 30-40 seconds or until chips are melted, stirring once. Spread over cereal layer., In a microwave-safe bowl, combine the remaining corn syrup and remaining butter. Cook on high for 45-60 seconds or until butter is melted, stirring once. Add chocolate chips; cook 30-40 seconds longer or until chips are melted, stirring once. Spread over top., Sprinkle with peanuts and reserved pretzels; press down gently. Cover and refrigerate 30 minutes or until set. Cut into bars. Store in airtight containers.