Mix the flour, oats, brown sugar and baking powder in a bowl. Stir in the melted butter until it forms a wet crumbly consistency.
Take half the crumble mixture and dump it into an ungreased 13x9 pan. Bake in a 350F oven for 15 minutes.
Unwrap the caramels and pout in a glass or stainless steel bowl with the milk. Place on a pot that is half filled with water. Bring the water in the pot to a boil. This will slowly melt the caramels in the bowl. As you stir the caramel and milk will combine to create a smooth caramel sauce.
Once the pan comes out of the oven, sprinkle the chocolate chips evenly across the crumble base. Pour the caramel over the chocolate chips. Spread the remaining crumble mixture evenly on top and bake for another 10 minutes at 350F.