Preheat your oven to 350°F. Line baking sheets with parchment paper or silicone baking mats.
In a medium bowl, whisk together the rolled oats, flour, baking soda, baking powder, salt, and ground cinnamon. Set aside.
In a large mixing bowl, cream together the softened butter, light brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes.
Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix the dough.
Gently fold in the semisweet chocolate chips and chopped nuts (if using) until evenly distributed throughout the dough.
Use a cookie scoop or spoon to drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden but the centers are still soft. The cookies will continue to set as they cool.
Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.
