Preheat the oven to 375 degrees F (190 degrees C). Sift together the flour, baking powder, baking soda and salt. Set aside. Process the rolled oats in a blender or food processor until almost powdered, combine with the sifted ingredients.
In a large bowl, cream together the butter, brown sugar and white sugar until smooth. Beat in the eggs one at a time then stir in the vanilla. Gradually stir in the dry ingredients until well blended. Fold in the chocolate chips and pecans. Drop by rounded spoonfuls onto ungreased cookie sheet.
Bake for 8 to 10 minutes in the preheated oven. Allow cookies to cool on baking sheet for 5 minutes before removing to a wire rack to cool completely.