[Nyx] can use Absorb along with massive ally damage to nuke entire maps. This is primarily used in Arbitration defense missions to quickly progress through waves. The subsumed ability doesn't really matter because you'll spend most of your time channeling Absorb.
Absorb is the only important ability in this build. If you choose to run a subsumed ability the other three are equal options since they're never used.
Strength and Duration are increased by a bit so that your subsumed ability isn't completely unusable. Any of these mods can be replaced at your discretion.
[Energy Siphon] is usually a weak energy regeneration mod but here we only need a small amount of energy to activate and detonate Absorb. The downside of this nuke is that you're going to spend your entire energy bar every time you cast it due to the extremely high enemy damage. The only thing that matters is the initial casting cost.
Arcane Agility, Infested Mobility, and [Firewalker] help you to reposition or chase down items between waves. There aren't many replacement options on a nuke build. Arcane Consequence and Molt are also good options but require a bit of extra work to use properly.
NOTE*
This build doesn't work unless it's combined with other Nuke Support setups. Specifically Arbitration Defense frames. Explaining all the intricacies between their interactions would double the size of this guide. In simple terms you need another frame boosting an extremely high level specter, someone protecting the team, and a second [Nyx] with this same build to make Absorb have constant uptime.