Place oven racks in the upper third of the oven and preheat to 350 degrees F. (177 degrees C.)
In a large bowl with an electric mixer, beat butter, brown sugar, and vanilla until light and fluffy, about 1 minute.
Add eggs one at a time and mix until thoroughly incorporated.
Add oats, flour, baking powder, cinnamon, nutmeg, and salt. Mix on low speed until blended.
Add semi-sweet chocolate chips and mix until incorporated.
Drop batter by heaping teaspoons 1 1/2 inches apart onto greased or parchment-lined baking sheets. (we like a Silpat mat)
Bake for 10-13 minutes or until golden brown.
Cookies will be soft but will firm up as they cool. Let cool for 2 minutes before transferring to wire cooling rack.
These cookies are best eaten within a day or two of baking. They also freeze well.Nutritional information is approximate and was calculated using a recipe nutrition label generator.★ Did you make this recipe? Don't forget to give it a star rating below!