In a large mixing bowl, combine butter and sugars and use an electric mixer to beat until lightened and creamy (about a minute or two on high speed).
Add eggs and vanilla and stir until well combined.
In a separate, medium-sized mixing bowl, whisk together flour, baking soda, salt, and cinnamon (if using).
Gradually add the dry mixture to the wet, stirring until almost combined. Add shredded zucchini and fold into the dough until completely combined.
Add oats and chocolate and stir until evenly distributed.
Cover dough with plastic wrap and place in the refrigerator. Chill for 30 minutes before proceeding. While dough chills, preheat oven to 350F and line a baking sheet with parchment paper.
Scoop dough by rounded 1 ½ Tablespoon-sized scoops and drop on prepared baking sheet, spacing cookies at least 2” apart. Bake in 350F preheated oven for 12-13 minutes. Allow cookies to cool on baking sheet before enjoying.