I have the 2003 Pathfinder, and I installed the PAC AAI-NIS. Google for it, but I think you know what it is.
Ok, QX4 is like a pathfinder. Look at my radio. No SAT button, I use the RADIO button. Here's a picture.
Also, here's the back of my radio. It's been a while since I did this, but I think I'm holding the AAI-NIS plug, and I think it went in one of the black slots. The harness hanging down is the steering wheel controls.
So my advice is check the front and back of your radio, compare it with the pictures I posted. If you think they are the same, get the AAI_NIS. It works great. If it doesn't work, ebay it.