Preheat the oven to 350°F (175°C).
In a large mixing bowl, combine the cake mix, sweetened condensed milk, eggs, and vegetable oil.
Stir in the chocolate chips and vanilla extract until evenly distributed.
Pour the batter into a greased baking dish.
Drizzle caramel sauce over the batter, swirling gently with a knife.
Bake in preheated oven for about 30-35 minutes, or until a toothpick inserted comes out clean.
Allow the cake to cool in the pan for 10-15 minutes before serving.
Serve warm topped with your favorite ice cream or whipped cream, if desired.
