I quite like my Nox.
I've found that it performs best, not as a sniper, but as a mobile harasser against heavier targets. Bomb catapult is a wonderful addition to this role, as it can do a decent amount of damage over a rather large area, and if nothing else is great for suppression tactics.
Stick slightly behind and above/below a heavier ally, and use your mobility to prevent runners from getting away. Your main guns do pretty decent sustained damage, and I'm finding that other pilots tend to underestimate your threat when there's a dread or destro right next to you.
Corvettes are another matter, but they are kinda the hard-counter to arty, so it makes sense that they'd be a Nox's biggest threat. Just another reason to have that nearby teammate. Though, if you're paying attention, you can make them really regret a careless approach.