"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
That's gonna depend on the shape of the electoral bell curve -- and how far right and left on the curve independents and lukewarm partisans consider the major-party candidates.
Traditionally, centrist third-parties have a pretty narrow sliver to work with, because both major candidates run to the center as soon as they're nominated. And on top of the typical challenges facing third parties, Nunn has been largely out of the public eye for more than a decade; Cuomo-Nunn is a Democratic dream ticker -- if you're dreaming it's 1988.
Sounds “Third Party” to me. If he were any different, why would he need to run as an Independent?