Problem here is that the Barsen'thor as an entire army at his/her disposal. Whereas Nox's confirmed powerbase consists of a few fleets and no real ground forces to speak of. And Barsen'thor (as far as I'm aware) only possesses ground forces...
I'm still advocating
Darth Nox vs Barsen'thor (with all their resources at the end of the game*)
*not exactly, Barsen'thor before the ending ceremony and Darth Nox after the ending ceremony so they have all their resources at their disposal.
Edit: Another interesting combatant would be ESB Admiral Piett (including General Veers' ground troops).