LINE a 13x9-inbaking pan with parchment paper, letting ends extend up sides; PREPARE and BAKE brownie mix according to package directions, using prepared pan.
REMOVE from oven; COOL brownies on a wire rack for 30 minutes; REFRIGERATE until cold.
SPREAD chunky peanut butter in a layer over brownies.
PLACE chocolate chips and creamy peanut butter In a large, microwave-safe bowl; MICROWAVE in 30-second intervals until melted; STIR until smooth.
STIR in Rice Krispies; spread over chunky peanut butter layer.
COVER; REFRIGERATE until set, about 45 minutes.
REMOVE brownies from pan by lifting with parchment paper; CUT into 1" bars.
STORE in an airtight container in the refrigerator.
Per Serving (excluding unknown items): 7677 Calories; 508g Fat (55.0% calories from fat); 195g Protein; 739g Carbohydrate; 68g Dietary Fiber; 0mg Cholesterol; 4984mg Sodium. Exchanges: 13 Grain(Starch); 18 1/2 Lean Meat; 90 1/2 Fat; 35 1/2 Other Carbohydrates.