Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, and nutmeg until well combined.
In a large bowl, beat the softened butter and cream cheese together until smooth and creamy.
Add the granulated sugar and brown sugar to the butter mixture, and mix until well combined.
Add the egg and vanilla extract, mixing until fully incorporated.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the grated zucchini, grated carrots, walnuts, and chocolate chips if using.
Drop spoonfuls of the cookie dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 12-15 minutes, or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.