Preheat oven to 350F. Line an 9x13-inch pan with aluminum foil and spray with cooking spray. Lining your pan will make cleanup easier due to the stickiness of the caramel. Set the pan aside.
In a large microwave-safe mixing bowl, add the butter and heat in one minute increments stirring in between until melted.
In a large bowl add the melted butter, brown sugar, vanilla, and whisk until smooth.
Add the flour, oats, baking soda, salt, and stir until combined. Mixture will be thick.
Press half of the mixture to the prepared pan, and smooth it with spatula, to create an even, smooth, flat layer; set remainder aside.
Bake for 10 minutes.
While the crust is baking, prepare the caramel sauce. Combine caramels bites and heavy cream in a medium saucepan, and heat over medium-low heat to melt, stirring nearly continuously, until mixture is smooth.
After 10 minutes, remove pan from the oven and evenly sprinkle with the chocolate chips on the crust.
Next, slowly and evenly pour caramel sauce over the chocolate chips.
Finally, evenly crumble the leftover oatmeal-brown sugar mixture all over the top.
Place the pan back in the oven and bake for an additional 15-18 minutes or until edges are lightly browned and center is bubbling.
It's important to allow bars to cool completely in the pan before slicing and serving, This could take 4 hours, overnight, or at room temperature. You can speed up the process by placing the pan in refrigerator.