With a wire whisk, mix flour, baking powder and baking soda. Pour into a jar and pack down level with a heavy object.
Mix oatmeal in a blender. Grate chocolate bar and mix into the oatmeal. Pack on top of flour in jar. Add granulated sugar and pack down. Add brown sugar and pack down. Layer chopped nuts on top of brown sugar. Finish layering jar with chocolate chips until even with the top.
Use pinking shears to cut a 9-inch diameter circle from the fabric of your choice. Center fabric circle over lid and secure with a rubber band. Tie on a raffia or ribbon bow to cover the rubber band.