Preheat the oven to 350 degrees F (175 degrees C). Generously grease a 12-cup Bundt pan.
Beat cake mix, pudding mix, sour cream, oil, water, and eggs in a large bowl until smooth and well blended.
Stir in chocolate chips.
Pour batter into the prepared Bundt pan.
Bake in the preheated oven until top is springy to the touch and a toothpick inserted into center of cake comes out clean, 50 to 55 minutes.
Cool cake thoroughly in the pan for at least 1 ½ hours before inverting onto a plate. Sprinkle powdered sugar on top if desired.
