Preheat oven to 350 degrees F. Coat a 9×13-inch baking dish with cooking spray and set aside. In a large bowl, combine the flour, oats, brown sugar, baking soda and salt. Mix well. Stir in the melted butter and mix until crumbly. Press half of the mixture into the bottom of the prepared pan and bake in the preheated oven for 10 minutes.
In a medium saucepan, combine the caramels and milk. Warm over low heat, stirring constantly until caramel is melted and smooth.
Remove bottom crust from oven and sprinkle chocolate chips evenly over the top. Pour the melted caramel evenly over top of the chocolate. Top with the last half of the flour-oats crumbles. Bake for an additional 15 minutes. Let cool completely before serving.