Grease and flour a bundt pan; set aside. Preheat oven to 350°.

Combine all ingredients except chocolate chips (cake mix, pudding, sour cream, vegetable oil, water, and eggs) together in the bowl of a countertop mixer fitted with the paddle attachment. Mix on medium speed for 3-4 minutes, or until batter is smooth and uniformly mixed.

Fold in the chocolate chips.

Using a rubber spatula, scrape the batter into the greased bundt pan.

Bake at 350° for 60 minutes, or until a toothpick inserted into the center of the cake comes out clean. (Tip: There may be chocolate on the toothpick due to the chocolate chips in the cake.)

Allow cake to cool before flipping onto a large plate.

Using a medium-sized heavy sauce pan, add the butter, sugar, and evaporated milk. Heat over medium heat, stirring often, until it reaches a rolling boil. Continue to cook for 1 more minute, stirring constantly. Remove from heat and stir in the chocolate chips. Continue stirring until chips have melted and icing is smooth and fully mixed.

Immediately pour icing over top of cooled cake. (Tip: This icing hardens fairly quickly, so you'll need to work fast here.)

Allow cake to cool completely before slicing.