In large bowl, beat butter and sugars with electric mixer until light and fluffy. Add eggs, one at a time, then vanilla; blend well. Stir in flour, baking powder, baking soda and salt. Add flour mixture to butter mixture; mix until just combined. Stir in chocolate chips and walnuts. Drop by rounded tablespoonfuls onto ungreased cookie sheet. Bake 11-13 minutes or until golden brown.