I don't think it would be a precursor, or not for me at least. It's a complete photographic tool for working on images. Photoshop will work on any image file, will deal with text, borders, combining several images into one, removing large chunks of an image etc etc. NX2 is designed to work on a single photograph. It's a pure photographers tool with no illusions of being any use for a graphic artist. It 'adjusts' an image where as Photoshop will in addition 'transform an image'.If I understand correctly, NX is a supplement/precursor to something like Photoshop for simpler modifications? (snip) ,
I started with Hagen's book. Do the exercises. Lots to learn.
Where are they Tom? I can only find 10 lessons here http://www.capturenx.com/en/lessons/lessons/index.html.Have a look at our stickies here.
There are a lot free resources from Nikon linked - if you e.g. run through the linked 32 session from Nikon thoroughly, you might be more proficient with NX than some of so called "master users around the web!