Preheat oven to 350 degrees F (180 C). Line 12 muffin tins with paper liners, or mist with cooking spray. Set aside.

Wrap the grated zucchini loosely in a clean kitchen towel or a few paper towels and squeeze gently to remove some of the excess water. Set aside.

In a large bowl, combine flour, oats, baking powder, baking soda, cinnamon, and salt. Whisk briefly to combine.

In a separate bowl, combine the eggs, Greek yogurt, honey, oil, and vanilla. Whisk until smooth. Add the grated zucchini and chocolate chips; stir to combine.

Pour the yogurt-zucchini mixture into the dry ingredients, and stir just until combined. Do not overmix - err on the side of having a few streaks of flour.

Divide the batter evenly between the 12 muffin tins, and bake for 18-20 minutes, until a toothpick inserted in the center of a muffin comes out clean or with moist crumbs. Transfer the pan to a cooling rack, and remove muffins after 10-15 minutes. Serve immediately or store at room temperature for 2-3 days.