Preheat oven to 350°. Whisk dry ingredients (flour, baking soda, baking powder, salt, cinnamon and nutmeg) in a bowl.
In a separate bowl, beat together butter and sugar with an electric mixer. Add eggs and vanilla.
Add dry ingredients and mix until smooth.
Stir in chocolate, oats, and nuts by hand. Form dough into small balls and place on a baking sheet. Bake for about 10 minutes, until cookies are light brown at the edges.