FCP7- sub frame nudging of audio?

Is it possible to nudge an audio file in the timline and incrments less than a frame?

Yes, sort of.
You can slip sync of audio in sub frame increments which may suffice for your needs.
It's been too long since I did this in FCP7 for me to tell you how from memory.
There's this



Or this
[filmdoctor.net]

ak
Sleeplings, AWAKE!