Preheat the oven to 350°F and line a 9×13-inch baking dish with parchment paper, including up the sides. Spray with nonstick cooking spray.
In a large bowl combine oats, flour, baking soda, and salt. Whisk to combine.
In a separate large bowl, add sugar and butter. Use a hand mixer to cream together until fully incorporated. Add eggs and vanilla and continue mixing until smooth.
Adding one cup at a time, mix in the flour mixture.
Spread ⅔ of the mixture (about 3 cups) into the prepared pan. Set aside.
Pour milk chocolate chips on top of the mixture. Pour the caramel sauce over the milk chocolate chips.
Carefully start placing flattened dollops of the remaining cookie dough over the caramel. I find it works best to pick up a small handful, flatten it in your hand a bit, and then place that directly on top of the caramel. Do this with all the remaining dough. It is okay if there is some caramel showing.
Bake for 38-40 minutes, or until lightly browned.
Let the bars cool on the counter for 30 minutes. Then transfer to the refrigerator to chill for an hour before cutting and serving.