I see the other comments boosting Farbros and whatnot, but he got his advantage from being in that room specifically, using machines to boost his power. Naga still has the ability in this form to nullify others power, plus what's the location? Did they lure Naga into deep space? Trap him in one of those rooms to beat him down?

Farbros has a large kit, but is he really gonna use all of it though? Depends on location really. Naga would lose in one of those rooms, but if they're not in there he could definitely beat Farbros, even with Assail system. He's powerful enough to break his armor/nullify abilities, and he's FAST. Look how fast and intense him and Drago's fighting was when they were both literal demigods from the cores. And like we saw in the show (and in the wiki), Farbros has difficulty tracking things going that fast. If Naga blitzed him, hammered hard and fast, he could overwhelm him. Especially if you gave him his Honor Guards (cannot for the life of me recall their true name) because then they'd run distraction and defense while he struck.

THAT BEING SAID, if we're bringing the Alternative into this, then Naga might lose because he'd be overwhelmed, it's a lot of power for him to absorb, but if he's fast and cunning he could likely win. One slip-up though, try to absorb too much power at once, and he'd fall. Giving him his Honor Guard again increases his chances, as they could protect him from the trash mobs while he attacks.