Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition, and then stir in the vanilla extract.
In a separate bowl, whisk together the flour, baking soda, ground cinnamon, and salt.
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Fold in the diced apples, rolled oats, and nuts (if using) until evenly distributed.
Using a cookie scoop or spoon, drop spoonfuls of dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 10 to 12 minutes, or until the edges are lightly golden.
Remove from the oven and let the cookies cool on the baking sheet for a few minutes before transferring them to a cooling rack to cool completely.