Looks like I'm going to have to eat my words

I should have said the LE Pathfinder would have made for a straight swap as it uses the same bezel.
If the donor QX4 has navigation, you might be able to finagle it in, but it's probably going to be more trouble than its worth. Ninjakills1 was able to
put that climate control unit in the stereo slot when he removed the navigation, but if I recall he had to do some trimming to get it to work.
The other twist is that would move the climate controls to the bottom which will mean new brackets for you.
If the QX4 does not have navigation, it'll have this other climate control unit style. You could probably get that one to work, but it'll take some rewiring to a different connector at minimum. The rear defrost button is also integrated into the unit instead of underneath the hazards button.
The bottom section will also change a bit, but that wouldn't be a problem in your case.
Unless you're interested in adopting the new climate controls or are up for a challenge, it's probably more worthwhile to buy one off eBay, like
this one or
this one.
Hope that gave you what you were looking for!
