Grind the oats into a fine powder (basically, making your own oat flour). Mix them with the flour, baking soda, baking powder and salt, then set aside.
Using an electric mixer, beat the butter and both sugars until light and creamy. Add eggs and vanilla and beat until well blended, scraping side of the bowl often.
Stir in the flour mixture, chocolate and nuts.
Roll into balls and place two inches apart on a cookie sheet. Bake for 10 to 12 minutes at 375 degrees or until cracks form on the surface. The cookies will take longer if you made the dough balls large or they are very cold.
Let the cookies cool on the baking sheet for about 3 minutes, then transfer to a wire rack to finish cooling.