I've tried that doubler in the PX strip and I don't care for it. It makes vocals sound too tinny for my taste.
I've found the only way to do it and make it sound good is to not take any shortcuts and do double takes and mix them together.
If you were going to try a technique like you are explaining with Nectar ... I'd just clone the track, use Melda's pitch correction VST (It's free) on the clone and nudge it. V-vocal isn't meant to be used with whole tracks. Only very small edits on just a few notes. The Melda one can be thrown in an FX bin and you can adjust how sensitive it is.
If you don't want the overhead of processing the tracks, just send the tracks to a bus, export the bus, Archive the tracks, and import the bus export.
But ... I know how you feel about free 3rd party VST's ... and I understand.
Good luck.