A Nitro retheme on it's own? no probably not
But looking at that area it's kinda in crisis. It's kinda inbetween the pine barrens and movie town, no cohesion whatsoever. If I'm looking at Great Adventure as the new Six Flags management you're trying to make parks like Great Adventure a higher ticket experience. And to do that you generally need to have a more cohesively themed park/experience. This is the direction that the most successful parks in the chain are going in for a reason (before someone says it, Cedar Point is an outlier and always will be, its known across the country as "the coaster capital" and that means there is a completely different set of expectations). Looking at the park there's only two/three areas that don't need a major overhaul, those being main street, plaza de carnival, and movie town (needs some work but nothing extreme). Everything else needs a major overhaul. Right now the attention is and should be on the boardwalk and golden kingdom, but after that I would put Nitro's plaza/pine barrens as the next on the list.
As for the whole nostalgia thing....nostalgia sells, but is Nitro really that nostalgic? Sure its an older ride but it's part of the very end of the "nostalgic era", I don't know many locals who really miss the post-recession era of great adventure. You want to sell nostalgia? You make a modern day Scream Machine, Freefall, Rolling Thunder, (prob not lightnin loops....for obvious reasons) you bring back the rainbow logo.
We've seen this new company give much more iconic rides a brand new theme...Intimidator 305 anyone?
I don't know what this new theme would be, its kinda hard to theme a giant metal box station, but I could definitely see them trying to expand upon the pine barrens theme and make it a legitimate themed area, rather than whatever the hell it is now. But this is the direction the company is going in, look at how great Jungle-X-pedition, Adventure Post, Fiesta Village, and Aeronautica Landing are. That's the future these parks area hopefully going in.