Mix the Cake Base: In a large bowl, combine the dry chocolate cake mix with the melted butter, stirring until the mixture resembles coarse breadcrumbs with a slightly chunky texture, about 2 minutes.
Spread the Mixture: Press this mixture evenly into the bottom of a 9x13 inch baking dish, creating a firm, even layer that covers the entire bottom.
Whisk the Pudding: In a separate bowl, whisk together the instant chocolate pudding mix with the whole milk until smooth and thickened, about 2 minutes of steady whisking.
Spread Evenly: Pour the pudding mixture over the cake base, spreading it carefully with a spatula to create an even layer.
Add the Chocolate Chips: Sprinkle the mini semi-sweet chocolate chips evenly over the pudding layer, distributing them across the entire surface.
Bake: Place the dish in a preheated 350 degree Fahrenheit oven and bake for 25 to 30 minutes, until the edges are lightly golden and the chocolate chips are melted into the pudding layer.
Cool Slightly: Remove from the oven and let cool for 10 minutes before serving, allowing the layers to set without becoming too firm.