Preheat the oven to 350. Prepare the pan with grease and parchment paper and set to the side.
Shred the zucchini using a box grater.
In a large bowl, combine the oil, peanut butter, brown sugar, eggs, sour cream, and vanilla. Mix with a whisk until just combined.
Add in the flour, baking powder, baking soda, and salt. Mix until there are no streaks left in the batter.
Fold in the zucchini and chocolate chips with a rubber spatula, making sure they are evenly distributed throughout the batter.
Pour the batter in the loaf pan and bake the cake for 55-65 minutes. A toothpick will run clean when the cake is done. Let the cake cool and a cooling rack until room temperature.