Preheat oven to 180 degrees C. Grease baking trays.
In a large bowl, cream together the margarine, white sugar and brown sugar until smooth. Beat in the eggs one at a time then stir in the peanut butter and vanilla.
Combine the flour, cocoa, baking powder, bicarb soda and cream of tartar; stir into the sugar mixture. Mix in the oats, walnuts and chocolate chips. Drop by rounded spoonfuls onto the prepared baking trays.
Bake for 8 to 10 minutes in the preheated oven. Allow biscuits to cool on baking tray for 5 minutes before removing to a wire rack to cool completely.