Preheat the oven to 350 degrees F (175 degrees C). Generously grease a 12-cup Bundt pan.

Mix together cake mix, pudding mix, sour cream, oil, water, and eggs in a large bowl until 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 1/2 hours before inverting it onto a plate. Sprinkle powdered sugar on top if desired.