I disagree. Nistune is a great addition to the car even with a standard turbo. It will not only future proof it if she wishes to get an exhaust cooler etc. put on but will improve the shit fuel economy a stock skyline has too. Forget piggybacks that's a thing of the past. My 2c.
Personally I am a huge fan of Nistune as Gtsboy said PowerFC is good but older tech and discontinued where as Nistune has ongoing development and support available.
It's also the first step of Frankensteining a car. Just get a manual boost tee and wind it up to 10psi no more and the stock ecu will handle that. No butchering wires required and can be removed if need be.
Walk away mate. That car is bent. Don't rush this look at as many as you can and the right one will pop up. Patience will yield you a result you'll be happy with.
Look up a guy called Toshi Tune on FB or here. I don't think he's been on this forum for a while but he does remote tunes while you drive. He is good with Nistune. Sounds crazy but might be a good option for you if you don't have anyone there to do it. He is very very good "Japanese style tuning" is his motto.
Just dont do it. I'm with GTSBoy not tearing you down mate, but you'd be better off getting a 25det and all ancillaries that come with that motor including ecu and be done with it. Keep the 32 ecu for nistune and boogie ?
Have you tried something as simple as taking the j-pipe off and getting some carb cleaner and a rag onto the throttle body? I did that a while back made a world of difference.