Hmm i dont know who is stronger but Nokken got a brother,
Fossegrim he lives in Artery zones.
And since Artery are harder that Meadows i can gues that Fossegrim are even harder that Nokken.
Also Liberator Centry guns are not that good. try Umpire guns instead, they hit from 1000 and up. I think that you can find them in Milky Way