+1!!!
here's a picture I posted on Amazon.com of the hitch I installed on my Qx4:

site:
Amazon.com link
To the left of the picture is towards the front, to the right of picture is towards the rear. You can see the spare tire there too for reference.
The picture is just one side... but it's a pretty straightforward install. Like others have said, I do believe that a 2nd person does make it a little easier, but 1 can do it with some sliding back-and-forth between sides. If you do it yourself, you just have to get at least 1 bolt threaded a little bit, support the hitch while sliding to the other side to get 1 bolt threaded in a bit.
here are the steps I took to do this:
1. On driverside, there is a airbox of some type, doesn't look critical to the overal function of the car anyhow so don't worry too much about small damage to it. There are 3x 12mm(IIRC) screws that hold this box in. Remove those 3 screws and let the box hang down.
2. clipped into this box is a plastic cannister I believe is a water drain outlet, The tube that runs down to it can be unplugged to allow the box to hang lower. The reason for lowering the box is to gain easy access the bolts.
2a. be careful lowering that box, there will be a lot of sand, dirt, dust, debris that will fall down. So wear some eye protection so it doesn't get into your eyes, and close your mouth so you're not having a dirt-y lunch
3. remove the tie-down plates, 3x bolts on each side (driver & passenger). I believe these are 19mm IIRC
4. brush away any dust at the frame and get ready to install hitch.
5. if you're doing this yourself, most likely the easy way is to use your a leg to hold up one end of the hitch, while you screw in the the other end. 1 bolt should hold it in temporarily. No need to tighten down, just get it in where it won't fall out when you move to the other end
5a. while still supporting the hitch, shimmy your way to the other side, and thread a bolt in. Since the other side is being held in by 1bolt, you may or may not have to support it with your legs, but you may need to adjust the angle a bit to get your bolt threaded.
5b. You might consider using some anti-seize grease on the bolts to make the bolts tighten down a little easier, else you might get the metal-to-metal "scream" when they start getting tight
6. now the hitch should be able to hang along your frame without you holding it there.
6a. it'd be my suggestion to shimmy back and forth between sides threading 1 bolt at a time, or you can finish bolting the remaing 3-bolts on one side and move to the other and finish that side's 3-bolts
7. hand-tigthen or use a ratchet to snug up the bolts
7a. get the torque bar, and set to "68 ft-lbs". Again, i would suggest you torque them down 1 bolt per-side at a time... meaning torque 1 bolt on driver side, then go to passenger side and torque the same bolt. The reason for this is that the hitch is not an exact fit to the frame, so the bolts will squeeze the hitch to the frame. To make all the pressures on the hitch somewhat equal and help a little with alignment, I'd do 1-bolt per side at a time.
8. re-install that box you lowered and re-connect that drainage-hose and you're set!
Next up.... hitch wiring kit!!!

again, I bought from Amazon.com:
Amazon.com Hopkins Plug & Play 43565 T Connector Wiring Kit For Nissan Pathfinder '96-03
You'll have to remove the side-panels from the cargo side-panels to get to the wiring behind the brake lamp.
When I get more time, i'll post up a mini-step-by-step if you need it, but it's not all too bad.