Yep ... you have to disconnect the front drive shaft to remove bank 2 sensor 2 (I asked the Nissan tech how he removed the sensor).

When all was said and done, I actually needed to replace only a single sensor (bank 2 sensor 2). The other sensor (bank 1 sensor 1) did not need replacing (even though it's trouble code was set). I tested bank 1 sensor 1's heater circuit voltage, power circuit voltage, heater continuity, and sensor output millivolts (using a digital meter and backprobe) and all tests looked OK. So I just had bank 2 sensor 2 replaced and all codes erased. The work was done last Tuesday and so far so good (no SES light).

IMHO ... if you are going to wash the engine, do yourself a favor and cover those O2 sensor pigtails with tin foil, plastic, or some other suitable material.