Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large bowl, combine the rolled oats, pumpkin puree, almond butter, honey (or maple syrup), and brown sugar. Mix until well combined.

Add the vanilla extract, baking soda, ground cinnamon, ground nutmeg, and salt to the mixture. Stir until everything is evenly incorporated.

If using, fold in the dark chocolate chips and chopped walnuts or pecans to the cookie dough.

Using a tablespoon or cookie scoop, drop spoonfuls of the dough onto the prepared baking sheet, spacing them about 2 inches apart.

Flatten each cookie slightly with the back of a spoon, as they will not spread much while baking.

Bake in the preheated oven for 12-15 minutes, or until the edges are golden brown. The centers will look slightly soft but will firm up as they cool.

Remove from the oven and let the cookies cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.