In a small bowl, combine flour, cinnamon and baking soda, set aside.
In a large mixing bowl, beat butter and sugar, until well combined. Add the egg and vanilla extract, beat until light and fluffy. Gradually add zucchini and flour mixture, beat until well combined. Stir in oats, nuts and chocolate chips. Cover and refrigerate for 4 hours or overnight.
Preheat oven to 375 degrees. Lightly grease or line baking sheets with parchment paper.
Drop cookie dough by rounded teaspoonful 2-inches apart onto prepared baking sheets. Lightly press each dough ball down with your fingertips to flatten slightly.
Bake for 9 to 11 minutes or until light golden brown around edges. Cool on baking sheets for 2 minutes then remove to wire racks to cool completely. Store in tightly covered container at room temperature.