Grate the zucchini using the largest hole on a box grater. Gently blot excess liquid using a paper towel.
To a large bowl, add the oats, flour, baking soda, salt, and cinnamon.
In a medium bowl, combine the zucchini, coconut oil, maple syrup, egg, and vanilla. Add to the flour mixture, and use a wooden spoon or silicone spatula to fully combine.
Add the walnuts and chocolate chips, mixing until evenly distributed. Cover with plastic wrap, and let chill for 30 minutes.
Preheat the oven to 350F. Line two baking trays with parchment paper.
Roll 1 ½ tablespoons of dough, and place 2 to 3 inches apart.
Bake for 12 to 14 minutes, or until the edges are golden. Remove from the oven, and let cool on the baking tray.
Keep in the fridge for up to one week, or freeze in an airtight container for up to 3 months.