Oh god, I love NX because you don't have to open 11tybillion images, Lightroom and all the rest of then get right up my nose, with all that import export crap.
I think the software you'd need is Nikon Picture Project (I could be wrong), that hit the bin many moons ago, bet I've still got it on disk somewhere.
hum, reading you're post again, I'm not sure I answered your question, do you just want to open 1 image or a great pile of them all at once ?