Combine first 4 ingredients in a small bowl. Beat butter and sugars in a large bowl until creamy. Beat in pumpkin, egg and vanilla until well mixed; gradually beat in flour mixture. Stir in chips and nuts. Drop by rounded tablespoon onto greased baking sheet; flatten slightly with back of spoon or greased bottom of glass dipped in sugar. Bake in preheated oven at 350 degrees F for 11-14 minutes. Cool for 2 minutes, remove to wire rack to cool completely.