PREHEAT oven to 350° F.
COMBINE flour, baking powder and salt in a medium bowl. Beat butter, sugar and vanilla extract in a large mixing bowl until creamy. Beat in eggs. Gradually beat in flour mixture. Stir in 1 cup morsels and nuts. Spread into ungreased 13x9-inch baking pan. Sprinkle with remaining morsels.
BAKE for 30 to 40 minutes or until wooden pick inserted in center comes out clean. Cool in pan on wire rack.