Preheat oven to 350° F. Put parchment paper on baking sheets.
Shred zucchini and squeeze out all the juice in your hands so that the batter will not be too wet.
Combine flour, cinnamon, baking soda, and salt in small bowl.
Beat butter, sugar in large mixer bowl until well combined. Add egg and vanilla extract, beat well. Add zucchini; gradually beat in flour mixture. Stir in oats, nuts, and chocolate chips. Place the dough onto prepared baking sheets one tablespoon at a time.
Bake for 9 to 11 minutes or until light golden brown around edges. Cool on baking sheets for 2 minutes; remove and place on a wire rack to cool completely. Store in tightly covered container at room temperature.