I've had similar problems in my R34, and whilst the R32 system is hydraulic, I'd assume it's reasonably similar.
What you'll probably need to do is set the front steering rack straight (so that the steering wheel angle sensor is straight), then put the steering wheel on straight, then reset the system (disconnect battery). That should make it re-learn where HICAS is.
If the mechanic is unsure about setting the front steering rack straight to the steering wheel, you might be best to go see Nissan and get the car put on CONSULT. They can read the steering angle sensor from HICAS and advise/adjust appropriately.
Alternatively, you can do as the previous poster said - and just replace with a lock-bar - but that may have legal / engineering implications.