Preheat oven to 350 degrees F. Grease and flour 2 loaf pans and set aside.
In a medium bowl, whisk together flour, cinnamon, salt, baking soda, and cocoa powder.
In a large bowl or the bowl of a stand mixer, beat together the oil, granulated sugar, brown sugar, and eggs, about 1-2 minutes. Add vanilla and sour cream and mix until combined.
If shredded zucchini is especially wet, place it in a strainer and gently press out excess liquid. Then stir the zucchini into the batter.
Stir a spoonful of the flour mixture in with the mini chocolate chips. Then add the rest of the flour mixture to the batter and stir until just combined. Stir in chocolate chips.
Divide batter evenly into the two prepared pans. Sprinkle topping over each.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs, not goopy batter. Let the bread cool 5-10 minutes before removing from pans.