Preheat oven to 350-degrees and grease a 9" x 13" baking dish.
Add the melted butter, brown and white sugar, vegetable oil, vanilla extract, and eggs to a large bowl and mix well.
Next, sift the flour, unsweetened cocoa, and salt together.
Add the sifted ingredients to the wet mixture and mix until combined.
Pour 3/4 of the chocolate chips into the batter and mix.
Spread half of the brownie batter into the bottom of the prepared baking dish and set aside.
Unwrap all of the caramels, add them to a medium-sized microwave-safe dish, and pour the sweetened condensed milk over the top.
Microwave the caramel mixture in increments of 30-seconds, stirring in between until melted.
Pour the melted caramel mixture over the top of the brownie mixture and spread it to the edges.
Add the rest of the brownie mixture over the caramel layer and spread out (it's ok if the brownie mixture doesn't completely cover the caramel layer).
Sprinkle the remainder of the chocolate chips on top and bake for about 40 minutes.