Grandma Loretta used to throw this together before the game even started, and it always vanished while it was still warm.

Sprinkle the chocolate chips evenly over the tops of the three pans. Next, scatter 1 cup of the chopped pecans over the pans, saving the remaining 1/2 cup for later. Gently press the chips and nuts down just a bit with your hand or the back of a spoon so they settle into the surface.
Cut the remaining 1/4 cup (1/2 stick) of butter into very thin slices. Lay the slices across the tops of the pans, spacing them out so each pan gets several little pats of butter. As the cake bakes, this butter will melt down into the dry spots and help create that glossy, crackled top.
Place the baking sheet with the three foil pans into the preheated oven. Bake for 30–40 minutes, rotating the pan halfway through if your oven has hot spots. The dump cake is done when the edges are bubbly, the top looks mostly set with some shiny, crackled areas, and a few spots may still look a little gooey—like a cross between brownies and pudding.
About 5 minutes before the cakes are finished, sprinkle the remaining 1/2 cup of chopped pecans over the tops of the pans and return them to the oven. This last-minute toasting gives the pecans a deeper flavor and keeps them visible and crunchy on the surface.
Remove the baking sheet from the oven and let the dump cakes cool in their foil pans on the counter for at least 15–20 minutes. They will firm up slightly as they sit but should still be warm and spoonable. The tops should look glossy and crackled with toasted pecan bits scattered across.
To serve, take a big spoon and scoop the warm dump cake straight from the foil pans into bowls. Make sure each serving has some of the gooey middle, the crackled chocolate top, and plenty of pecans. If you like, top with vanilla ice cream or whipped cream and enjoy while it’s still warm—just the way it always disappeared at Grandma Loretta’s house before the game was even halfway over.
Variations & Tips
For a deeper chocolate flavor, use a dark chocolate or devil’s food cake mix and add 2 tablespoons of unsweetened cocoa powder to the dry mix before you spread it into the pans. If you like a little sweet-salty contrast, sprinkle a light pinch of flaky sea salt over the cakes right when they come out of the oven. You can swap half of the pecans for walnuts or chopped peanuts if that’s what you have in the pantry, or add 1/2 cup of shredded coconut for a German-chocolate twist. For a less rich version, use only sweetened condensed milk plus 1 cup of regular milk and cut the butter down to a total of 1/2 cup; the cake will be a bit more cakey and less gooey. To make this ahead for a crowd, assemble everything in one large disposable 9×13-inch foil pan instead of three smaller ones and bake 5–10 minutes longer, until bubbly and mostly set. Leftovers (if there are any) can be cooled, covered right in the foil pan, and refrigerated; warm individual portions in the microwave for 20–30 seconds to bring back that fresh-from-the-oven, game-day goodness.