There is a Nissan locking kit which works well, however I assume that you will not have this as most the Nissan garages do not have it either.
You can fabricate your own or lock the fly with a suitable tyre lever or a wedge shape piece of hardwood.
The locking can all be carried out by removing the R/H inspection plate on the bell housing opposite side from the starter motor, or remove the starter motor.
Very simple and even easier if a 2 man operation as the bolt is tight, however any of the above methods will work.