Line a 9x13-inch baking dish with parchment paper or aluminum foil.
Place semisweet chocolate chips in a microwave-safe bowl; heat in microwave until melted, about 1 minute. Stir chocolate until smooth.
Combine white chocolate chips and butterscotch chips in a separate microwave-safe bowl; heat in microwave for 1 1/2 minutes. Stir mixture until smooth. If chips aren't completely melted, continue heating in the microwave in 10-second intervals, stirring after each interval until smooth.
Stir crispy rice cereal and peanut butter into white chocolate-butterscotch mixture; pour into the prepared baking dish.
Spoon semisweet chocolate in lines across the peanut butter mixture. Run a knife in the opposite direction of the chocolate lines to achieve a swirled, tiger-stripe pattern. Cover dish with plastic wrap and refrigerate until set, at least 10 minutes. Cut into small squares.