Get one of those really strong little magnets and try to coax the nut close to the drain plug from the outside on the bottom of the pan. It should drag the nut toward the drain hole. You can test the procedure on a scrap piece of sheet metal and a similar sized nut.
Carl

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission