It would be Narducci's (and the old guard from the Scarfo era) for the taking. But it probably wouldn't be much of a viable mafia 'family' at that point anymore.
Nobody (except for Nicodemo himself) knows exactly what he could/would give up. But I imagine he could sink pretty much the entire hierarchy and several capos. Merlino, Mazzone, Ciancaglini, Ligambi, Mikey Lance, and several others.
It would stay
viable if they start making a bunch of guys. Might not be as strong, but still
viable.