Add parchment paper to 13x9 baking dish and set aside.
In a saucepan over medium heat, melt the butter. Then add karo syrup and bring just to a bubble. Then add peanut butter and stir until fully incorporated. Pour mixture over cereal and quickly stir together.
Transfer cereal to baking dish and use a spatula to press into a even layer in the baking dish.
In a small microwave save bowl, add chocolate chips. Cook in microwave for 30 seconds then stir. Continue to cook at 15 second intervals, stirring each time, until fully melted. Then immediately pour over top of cereal mixture and use a spatula to spread out evenly over entire pan.
Place in refrigerator to cool for at least 2 hours. Remove and cut into 16 bars.