I don't think O'Charley's keeps their aircraft in Nashville anymore.
Gaylord runs an Astra out of Hangar 2; a very, very tight flight department - just two guys with a contract alternate that shows up on the VERY rare occassion one of the two is sick or has a family emergency.
I checked out their Chief Pilot a while back on a Mooney he wanted to use while I was Chief Flight Instructor in the same hangar; he was very tight-lipped about the whole thing and definitely gave off the impression that there would be an opening when one of them was placed six feet under.
Hangar 5 houses a construction company (did some charter work for them back in '96, just can't remember their name right off-hand). They had two Beechjets and a Bell Jetranger (no turboprop - that's why they needed us sometimes) and I still see their aircraft in there from time to time when I'm on the field.
B&C Aviation runs two Lears and a Falcon 20-5BR for Allan Jackson out of Hangar 7, Donnie Mudgett is the Chief Pilot, but it's difficult to break into as well, they have to see you around quite a bit and like the way you present yourself before you can really approach them about it.
Someone is in Hangar 8 (I don't know who - it changes pretty regularly) and Hangar 9 is a check-running operation running Barons.
If you want their contact numbers, just call Signature (they control everything from Hangar 7 to the North) or Mercury (they control everything from Hangar 6 to the South).
Tune might have a few more corporate aircraft - try calling Corporate Flight at John C Tune to find out - if they'll tell you (probably won't).
Nashville jobs are very scarce indeed, especially corporate ones - lots of big business, just most of them have their aviation ops headquartered elsewhere (Dell, Bellsouth, etc) and lots of competition - MTSU churns out a hundred new pilots every semester, flight instructors have several thousand hours and are competing for all the entry level jet and turboprop stuff and have nothing better to do than hang around and rub shoulders with the managers and operators there.
Good luck!