Preheat oven to 350°F and line a baking sheet with parchment paper.
Begin by browning the butter in a medium saucepan over medium heat. Let the butter melt and continue cooking until it turns brown, being careful not to burn it. Once browned, remove from heat, transfer to a large bowl, and let it cool for 10 minutes.
Add coconut sugar, eggs, and vanilla extract to the cooled brown butter. Whisk until well combined.
Stir in all-purpose flour, rolled oats, baking soda, baking powder, and salt until a dough forms.
Fold in chocolate chips and pistachios, then use a cookie scoop to portion out the dough onto the prepared baking sheet.
Top each cookie with additional chocolate chips and pistachios, then bake for 10-12 minutes or until golden brown.
Allow the cookies to cool before transferring and enjoying!