In a large bowl, whisk together the flour, cocoa powder, baking soda, baking powder, espresso powder (if using), and salt.
In another large bowl, using a handheld or stand mixer, beat the oil, granulated sugar, brown sugar, eggs, sour cream, vanilla, and shredded zucchini until well combined.
Gradually mix the dry ingredients into the wet ingredients until fully combined. Stir in the chocolate chips. The batter will be slightly thick.
Divide the batter evenly between the cake pans.