Preheat oven to 350°F (175°C). Grease and flour a 12-cup bundt pan, coating all crevices.

In a large bowl, combine cake mix, pudding mix, eggs, sour cream, oil, water, and vanilla. Beat on medium speed until smooth, 1–2 minutes. Fold in chocolate chips.

Pour the batter into the prepared pan and smooth the top. Bake 45–50 minutes, or until a toothpick inserted comes out with a few moist crumbs.

Cool in the pan 15 minutes. Invert onto a wire rack and cool completely before topping.

Make caramel-pecan sauce: In a small saucepan, combine brown sugar, heavy cream, butter, corn syrup, and salt. Bring to a gentle boil over medium heat and simmer 2–3 minutes, stirring constantly, until smooth. Remove from heat, stir in vanilla and toasted pecans, and let cool slightly to thicken.

Make ganache: Heat cream until hot but not boiling. Pour over chocolate chips in a heatproof bowl. Let sit 1 minute, then stir until smooth and glossy.

Place the cooled cake on a serving plate. Spoon the caramel-pecan sauce over the top, letting it drip down the sides. Drizzle with the chocolate ganache. Let set 15–20 minutes before slicing and serving.