Combine all ingredients (except chocolate chips) in a medium-sized bowl and mix until smooth and creamy. Pour mixture into a 9×13 pan. Melt the chocolate chips in the microwave for 1-2 minutes. Stir chocolate, pour over the peanut butter mixture and spread with a spatula. Refrigerate for 1 hour, then cut while bars are still cool.
I cut the bars right after taking them out of the fridge, which is why they appear more unevenly cut than usual. If you take them out and let them sit for 15-20 minutes or so, then they will be easier to cut. They still taste amazing, though!