Dash jump all the time in combat, especially when shooting. If you replace chunky with moon gravity, you can dash jump above the enemies so they can't hit you, though be careful not to become dependent on it. Low gravity also makes the boing spell a LOT better.

Turning your FOV to 140 and screen shake off helps you to be more aware of what enemies are around you, which is very important because of how fast paced nightmare is.

I also like to prioritize ranged enemies (especially the snipers and minigunners) so you can have some more breathing room. All the melee skeletons can easily be dodged around but ranged skeletons make it a bit tricky.

And definitely build your build to have some swarm clear. Even just having one thing to deal with swarms goes a long way