In a large microwave safe bowl, combine brown sugar, white sugar corn syrup and mix well. Microwave on high for two minutes.
Remove bowl from microwave and stir mixture, then return to microwave for another two minutes, or until mixture begins to bubble and boil.
Remove from microwave and add 1-1/2 cups peanut butter. Stir until mixture is fully combined. Add cereal and mix until well combined.
Press into prepared (I used parchment once then PAM the next time, both worked well) 9x9 pan, using back of greased spoon to press evenly.
For Chocolate Topping:
Put chocolate melts into microwave for one minute, then remove and stir. Continue microwaving for 30 second intervals until chocolate is completely melted. Watch closely! When melted, spread evenly over cereal mixture.
Combine semi sweet chocolate chips and 1/3 cup peanut butter in small microwave safe bowl. Heat on medium power for two minutes then remove and stir. If necessary, put chips back in microwave for 30 second increments to fully melt chips. Stir until smooth, then spread over cereal mixture.
Let cool completely (if you can!), then cut into bars.