I've never seen a nuke which is actually 'controllable'
, I did heard it was possible though.
But anyway, you didn't want that to happen so lets fix that. Before I can help you though it would be rather handy if you would give me an unprotected map, since I can't open this one (or unprotect it, for that matter :/ ).
It might be that the nuke goes up again because it moves through a location at the bottom where the nuke AI is running, or something like that. Or it might be that the nuke gets deleted as soon as it gets down and a new one is spawned.
I suggest you move the locations so the nuke will not encounter any location on its trip.
Btw, did you notice that all those other ghosts who get spawned DO nuke normally?
PS: I'm not an expert with the nuke AI script, so forgive me if I sayd something stupid