Hi...i know of your Nixon but have not heard it myself...so all i can 'guess' is that you already have quite a good digital piece...quite good. That is good news!
If i were to start looking for detail but knowing something about the sound characteristics of Nixon...in the $1000 used price range, i would start with the Cary players and the Oppo Blu-Ray 95. The level of detail from the Oppo is really, really remarkable and it is quite a natural sounding player imho. Quite detailed/defined in a good way. Plus you can play any format you want.
The Cary's have a good reputation...you can see them at just above $1000...so maybe with a little haggle you can get it to just $1000. Good luck and hope that is somewhat helpful. You do have quite a good piece...enjoy.