Preheat the oven to 350°F. Line a 9×9-inch baking dish with foil and spray with nonstick spray.
In a large bowl, whisk together the 18 ounce brownie mix, 1/4 cup water, 1/2 cup oil, and 2 eggs until combined. Add 2 Tablespoons condensed milk and 1/2 - 1 cup chocolate chips, if using.
In a microwave-safe bowl, combine 11 ounces caramel bits and remaining 1/2 cup condensed milk. Microwave 1 minute. Stir. Microwave 15 to 30 more, if needed, until caramel is melted and sauce is smooth.
Spread 1/2 the batter into the baking dish. Pour the caramel sauce evenly over the top. Add the remaining batter and spread out evenly.
Bake 30 to 40 minutes, or until a toothpick inserted into the center comes out clean.
Let cool in baking dish before removing for easier cutting.
Notes
Wrapped caramels: I highly recommend finding or ordering caramel bits to make this recipe, as it saves time and the bits provide a softer texture to the caramel layer than the wrapped caramels. Brownies: If you want to make brownies from scratch, use my favorite homemade brownie recipe.