First, cream the butter with the sugars until it's airy. This takes about 2 minutes on a high speed from the mixer. Then, add in the egg and mix.
In a separate bowl, toss in the flour, baking powder, baking soda, and salt. Now, combine the dry and wet ingredients. Do not over-mix.
Once everything is combined, fold in the chocolate chips or walnuts.
Preheat the air fryer to 325℉.
When ready, add a piece of parchment paper into the basket and place scoops of cookie dough into the basket. Be sure to leave room for the cookies to spread. Place the basket back into the machine and cook for 7 minutes. If you make the cookies smaller or thicker you will need to adjust the time. I used a large 3 TB cookie scoop.
When the cookies are done, remove them and allow to cool for 10 minutes before serving.