Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper.

Cream the softened butter and both sugars together for 2-3 minutes until light and fluffy, scraping down the sides of the bowl.

Add the eggs one at a time, beating well after each addition, then mix in the vanilla extract.

In a separate bowl, whisk together the flour, baking soda, baking powder, and salt. Gradually add these dry ingredients to the wet mixture, mixing until just combined.

Gently fold in the oats, chocolate chips, and chopped pecans until evenly distributed in the dough.

Drop tablespoonfuls of the cookie dough onto prepared baking sheets, spacing them about 2 inches apart.

Bake in the preheated oven for 10-12 minutes, or until the edges are golden and the centers look slightly underdone.

Allow the cookies to cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.