Hmm…I just beat this on my first try, solo, with Miko, on normal difficulty, and Nova still had more than half her health.
So, a few things to consider…it was on normal, so the challenge wasn’t insane. I was solo, which also tones down the challenge. I was Miko, but the shroom is certainly no slouch in combat. But here’s the thing…I did the mission after reading these boards and I was terrified! I spent extra time gathering as many shards as I could, and my loadout is fairly cheap, so I had a lot of shards at the end. Being terrified, I walked every inch of the room and made sure I activated every defense possible before starting the encounter.
Once it started, I noticed a big strategic element that I luckily guessed with my counter defenses…the larger enemies are not nearly the threat that the weaker, low health enemies are. Those little guys are quick, and do a TON of damage to Nova. But, because they have little health, the defenses can take care of most of them for you. So, the strategy I suggest is this:
First, get thumper turrets on both sides of the room and make sure they stay up! Put an inferno trap on the main area that is next to Nova, and place a temporal trap on that pillar that’s touching Nova. The rest of the traps are up to you, but get them all up, and get an assault drone to follow you. That assault drone will take out a lot of the weak enemies amidst the chaos, leaving you to focus on the bigger enemies yourself. Keep an eye on the radar, and generally fight in that main area next to Nova. Very importantly, never go into the circle area around Nova unless you HAVE to clear out an enemy there, because this will attract more enemies to Nova and she is actually pretty weak. Keeping the enemies from touching her in the first place is key.
Work in tandem with your defenses, and success will belong to us all!
I truly hope this helps, and have fun out there! 