The important thing is the offset and hub bore if you're considering aftermarket (or another Nissan/Infiniti) wheel.
The offset is 50mm on the stock 18" and 20" wheels.
The hub bore is 66.1mm. Gotta keep them hubcentric.
We have a Platinum with 20" (obviously). I got a set of Murano "5-Y" 18x7.5" wheels for my snow tires. Exact same diameter, width, offset, and hub bore diameter as the Pathfinder 18" "5-horseshoe" wheels.