Preheat the oven to 350 degrees.
Grease a 10 - 12 cup Bundt pan. Set aside. See Notes on greasing.
In a small bowl, combine the vanilla extract and espresso powder, stirring to dissolve the powder; set aside.
In a stand mixer fitted with the paddle attachment, add the cake mix and pudding mix to the bowl; combine on low for about 30 seconds. You can alternatively use a hand-held mixer.
Add the eggs, sour cream, oil, buttermilk, cake batter flavoring, and vanilla-espresso mixture to the bowl. Turn the mixer to “stir” (or low) and blend the ingredients for 30 seconds or until the batter is mostly moistened. Alternatively, you can use an electric hand-held mixer.
Slowly turn the mixer to medium and set your timer for 2 minutes. Watch the timer. When 20 seconds remain, add the chocolate chips. Stop and scrape the bowl if necessary while mixing.
Using a silicone spatula, scrape all the batter into the greased Bundt pan, spreading the batter evenly in the pan. Smooth the top.
Bake in the preheated oven for 40 – 50 minutes. Check for doneness with a toothpick. You want a few crumbs, but not wet batter on the toothpick. Check at 35 minutes if your oven runs on the hotter side.
Remove the pan from the oven and let it cool on a rack for 20 minutes.
Invert the cake onto a cake plate/platter or cake stand. Be careful; the pan will still be hot. Allow the cake to slightly cool or come to room temperature if dusting with powdered sugar. If drizzling with ganache, allow the cake to cool completely… if you can wait that long.