I need a Nocturne AP build that is viable...
And the core component of it needs to be Frost Queen's Acclaim
. I need spooky ghosts to go with my spooky ghost Nocturne skin [zombie-nunu-hearts]
And the core component of it needs to be Frost Queen's Acclaim
. I need spooky ghosts to go with my spooky ghost Nocturne skin [zombie-nunu-hearts]

First we would have to make nocturne viable.

He doesn't scale from AP. Only his E scales.
Yes. It's happening.
PBE buff:
"Nocturne Umbra Blades (Passive) now has a .5 AP ratio."
(
or
) 

This should make you not utterly useless, Q + E or Frost Queens/Funblade should mean 2x Burn effect. Lots of slowing, with AP + AD Damage and AP Burst Damage. Nobody can escape you, and at that, hope to chase you.
Your Skill combo should be R>Gunblade>Q>E>AA. With slows, mild burst damage, and good AD damage, you should be able contribute enough for your team to follow up. It's really an assassin's build, but in an extended teamfight you can enter an exit on regular intervals.