Preheat oven to 350 degrees F. Lightly grease a 9"x5" loaf pan and then dust it with flour, set aside.Place the avocado in the bowl of your stand mixer fitted with the paddle attachment and beat until mostly smooth. Add the butter and continue to beat until light and fluffy, scraping down sides of bowl when needed.Add the sugar to the bowl and beat until combined. While mixing, slowly add the eggs one at a time, followed by the vanilla, melted chocolate and zucchini. Mix until incorporated.In a separate bowl whisk together the flour, cocoa powder, salt, cinnamon and baking soda. Add half of the dry ingredients to the wet ingredients, followed by the sour cream, and then finish by adding the remaining dry ingredients. Once fully combined add the chocolate chips and stir a couple times to get them all throughout.Pour the batter into the prepared loaf pan and bake for 70 to 75 minutes or until a toothpick inserted in the center comes out clean. Let cool for at least 25 minutes in the pan before attempting to remove and cool completely on wire rack.