Preheat the oven to 350 degrees.Grease a 9×5 loaf pan and set aside.In a large bowl, which together the flour, oats, sugar, brown sugar, baking powder, baking soda, cinnamon, salt and chocolate chips.In a small bowl, whisk together the buttermilk, egg, and melted butter.Add the wet mixture into the dry mixture and stir with a wooden spoon or rubber spatula, just until fully incorporated. The batter will be lumpy.Pour the batter into the prepared loaf pan and bake for 40-45 minutes until a toothpick inserted in the middle comes out clean.Let cool on a rack before slicing to serve.