Preheat the oven to 350 degrees F. Line a 9×9 square pan with parchment paper that covers the bottom of the pan and reaches up the sides.
In a large bowl, cream together the sugars, butter, and eggs.
In a separate bowl, mix together the flour, baking soda, and oats. Slowly mix the flour mixture into the sugar mixture until fully incorporated.
Spread 3/4 of this mixture into the prepared pan.
In a medium saucepan, melt the fudge ingredients (condensed milk, chocolate chips and butter) on medium heat, mixing until smooth.
Pour the chocolate mixture over the oat layer in the pan, then blob the remaining oat mixture on top of the chocolate.
Bake for 25 minutes. Remove from oven and let cool for at least 30 minutes, then refrigerate.