I have a 2003 Pathfinder, if you buy one with high miles here's what to look forward to:
Throttle plate screws that fall out and destroy the engine, common problem for this year Nissan. Mine did this, I recovered a throttle plate down the intake, it's too big to get all the way to the valves. The engine ate the screws, I lucked out because it still runs ok, although I'm sure a cylinder or 2 has 'shot peened' chambers.
The death wobbles. The rear of this car will sway side to side heavily at certain speeds,it gets scary. This is caused by the rubber bushings in the rear control arms that wear out. If you replace the arms with aftermarket (made to a price point) stuff, you'll have the problem again soon. Solution is use genuine Nissan parts, that are expensive, or poly bushings which work but are kind of a pain to install. Again, common problem.
Leaking oil pan. The original end seals on the oil pan of the VG35 will inevitably, after about 150k miles or so, harden and shrink. Oil will then leak out between the trans and the engine and it will look like a rear seal leak. To change a rear seal on this car, the trans and the engine oil pan has to come off. To remove the oil pan on Pathfinder, either hang the engine in place and remove the front subframe to get access or pull the engine, your choice. I pulled the engine. Again, common problem.
Leaking valve cover gaskets. No fun with the engine in the car, the upper intake has to come off. I did this one with the engine out of the car, much easier. These gaskets must be made of the same stuff the oil pan end seals are.
The foam rubber between the A/C condenser and radiator will deteriorate. When this happens you don't get much airflow over the condenser with the vehicle stationary. Symptoms are the A/C does not cool that well when the car is stopped. What's happening is the high side pressure is going way up and the compressor is not happy. It will let you know how unhappy by taking a dump.
The transmission will delay going into reverse when cold, eventually it won't go into reverse at all... Time to drop the trans and tear into it.
On cold starts you will hear the timing chains rattle, the guides and tensioners are worn and the chains are getting a bit slack.
All of the above and more has happened to my Pathfinder, if you google these things you'll get hits. This car is well taken care of, oil changes on schedule using synthetic, transmission serviced, cooling system etc. I like the car, the engine runs smoothly and it rides nice, but it sure is a maintenance hog.