Step 1: Prepare the pan
Preheat your oven to 350 degrees Fahrenheit and lightly grease a 9 by 13 inch baking dish.

Step 2: Mix the batter
In a large bowl, mix together the butter pecan cake mix, coconut pecan frosting, eggs, oil, and milk until everything is smooth and well blended.

Step 3: Add pecans
Fold the chopped pecans into the batter, making sure they are evenly distributed.

Step 4: Bake
Transfer the batter to the greased baking dish and smooth it out evenly. Bake for 30 to 40 minutes, or until a toothpick inserted into the center comes out clean.

Step 5: Poke the cake
Remove the cake from the oven. While it is still warm, use the handle of a wooden spoon to poke holes all over the surface, pressing deep enough for the sauce to soak through.

Step 6: Make the sauce
Place a saucepan over medium heat and melt the butter. Add the sweetened condensed milk and stir until the mixture is smooth and fully combined. Bring to a gentle simmer, then stir in the chopped pecans and remove from heat.

Step 7: Pour and cool
Slowly pour the warm praline sauce over the cake, allowing it to seep into the holes and spread across the top. Let the cake cool completely before slicing.