Nissan Patrol: Does two-stroke engine oil reduce engine noise?

I wouldn't do it, there's no justification for it. Some people might think there's a benefit in added lubrication of the valve train etc, but that's unlikely as diesel fuel does have some lubrication properties anyway. You might clog up the catalytic converter if you did run it on 2-stroke fuel, and it's likely to result in more exhaust smoke.