>Is there anything I can do other than watch and wait with a nuc ready to go out swarm hunting?
What you should have done before...http://www.bushfarms.com/beesswarmcontrol.htm
>Should I try to split the hive before the swarm?
> Take the queen and some frames to the nuc but leave the queen cells?
Why not give both sides some queen cells just in case.
>Should I leave the hive alone until it swarms
No. Split it.
> or is inspecting it again this weekend ok?
Inspect if you like, but I'd split it NOW.
>Should I put a super on top? (The hive's ready for it, if the it wasn't about to swarm. : )
That would have been a better idea sooner, but still won't always head off a swarm.http://www.bushfarms.com/beesfallacies.htm#noswarmwithsupers
>Should I feed the absconded hive after the swarm?
I assume you mean the hive that swarmed... I wouldn't. Why would you feed them? Are they starving? Is there anything blooming?http://www.bushfarms.com/beesfallacies.htm#feedingcanthurt