Preheat oven 350F. Coat baking sheet with nonstick cooking spray.
In mixing bowl, mix together butter, sugar, and brown sugar until blended. Add egg and vanilla, mixing until creamy.
In another bowl, combine flour, baking powder and baking soda. Gradually add flour mixture to butter mixture, mixing only until combined. Stir in oatmeal, chocolate chips and pecans. Drop dough by spoonfuls onto baking sheets.
Bake 10 to 12 minutes or until cookie edges begin to brown.