Ran the nightfall 3 times a little while ago, here's some real basic advice because it is one of those "oh come onnnnn…" nightfalls.
Firstly, about the modifiers. Don't jump if you can avoid it. Even though brawler is on you're not going to be using it much because it's hard to get in punching range without being melted. Match game is the important bit here.
Start of the strike: Recommend a solar primary, preferably not a hand cannon due to the range. This is for the wizards that all have solar shields.
Recommend a void machine gun (or whatever's safe at range) for the splicer captains due to void shields.
Omnigul herself: She's got an arc shield, so recommend an arc primary or secondary. I also saw everyone unloading heavy onto her which is a bit of waste, use the heavy on the ogres, knights and thrall which will be much more of a threat. DPS doesn't really matter with Omnigul because it doesn't really matter how fast you get her down, she still disappears 3 or 4 times then adds spawn.
I'd advise that when she shows up, just do enough damage to get her to fly away for a bit but concentrate on the adds, especially the thrall because those cursed buggers are what will cause deaths. Use the heavy on the adds and just use primary and secondary to whittle away her health.
As for subclasses, just go for survivability and orb generation, this a strike to live through, big damage isn't a big deal. That basically covers every subclass except for striker or blade dancer really though