Preheat oven to 180 degrees C. Grease baking trays.
In a large bowl, cream together the margarine and sugar until light and fluffy. Beat in the egg, then stir in the pumpkin and vanilla. Combine the flour, baking powder, bicarb soda, salt, nutmeg and cinnamon; gradually mix into the creamed mixture. Stir in the walnuts and chocolate chips. Drop dough by teaspoonfuls onto the prepared baking trays.
Bake for 15 minutes in the preheated oven, or until light brown. Cool on wire racks.