they are hard to get a hold of, I have tried regarding my 200sx project thats using a VQ ECU, I don't think they do anything with the non OBD2 ECU..... yep just checked and they don't list anything older then a 2003.
I think about the only options for VGs is remove the chip and have a socket put in or have Nistune put a daughter board in, with the VG you should be able to use a supported ECU (i.e. 300z) from another VG car, I know that the 300z ECU will plug right into a 2nd gen Maxima, not sure if you would have to repin for a Pathfinder