Preheat the oven to 350°F (175°C).

In a medium mixing bowl, combine the cake mix, milk, melted butter, and eggs. Mix by hand or with a hand mixer until fully incorporated and smooth.

Generously coat a Bundt pan with nonstick cooking spray. Pour the prepared batter evenly into the pan.

Bake for 35–40 minutes, or until a toothpick inserted into the center comes out with only a few moist crumbs and no raw batter.

Remove the cake from the oven and allow it to cool in the pan for 10 minutes. Carefully invert onto a serving plate and allow to cool completely.

In a small saucepan set over medium heat, combine the butter, cocoa powder, and milk. Whisk continuously until the butter is fully melted and the mixture is smooth.

Remove the saucepan from heat and gradually whisk in the powdered sugar until a smooth frosting forms.

Stir in the chopped pecans until evenly distributed.

Pour the frosting over the cooled Bundt cake, allowing it to drip naturally over the sides.

Let the frosting set before slicing and serving.