That's exactly what my HICAS used to do - steering wheel rolled over. Then when you hit 110kph, that's when HICAS turns off - steering wheel snaps straight, and it's a scary experience. In this situation, though - my HICAS light wasn't on.
Either way, I ended up talking to Nissan about it and they used their CONSULT to check it out. Turned out the HICAS steering sensor was off compared to where the wheel was. Basically when the steering wheel was straight, HICAS thought it was at an angle.
Basically what I had to do was get the HICAS system reset, and have the steering rack straightened up compared to what the steering angle sensor thought. It's been perfect since. I'm sure Nissan can advise and probably fix it for you. (Bit difficult to get it straight without the steering angle sensor output).