PREHEAT oven to 375° F.
COMBINE flour, baking powder and baking soda in medium bowl. Beat butter, granulated sugar and brown sugar in large mixer bowl until creamy. Beat in eggs and vanilla extract. Gradually beat in flour mixture. Stir in chocolate and nuts. Roll 1/2 cups-worth of dough into balls and flatten. Dough is dry, but do your best. 4-5 cookies should fit per baking sheet.
BAKE for 12 to 14 minutes or until light golden brown. Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.