This is a bit of a labor of love build. [Nyx] isn't a good Warframe, but this build makes her feel as close as possible.

The name of the game here is Energy Upkeep. We want to stay in Absorb for as much as possible. Using Nourish and Arcane Energize, along with [Primed Flow], we can upkeep our massive energy reserves. We also need to reduce the cost of Absorb, so a bunch of Duration and efficiency is needed.

This build only cares about how good your weapons are. If you can kill enough enemies to get energy drops, you'll be able to live forever without taking damage.

Your 2 can full strip acolytes and other enemies. Your 1 is best used controlling things like Arson Eximus Units for a heat proc, or Blitz Eximus for Blast procs, but picking up Napalms, Shield Drones, Drakk or Hyekka Masters aren't bad either.

Range doesn't impact any ability here except nourish. It does technically impact absorb, but only if you're trying to use absorb to [Protect] an area, and this build is more to [Protect] yourself.

I'd use 5 Yellow Archon Shards for Energy Orb effectiveness, or 5 Blue Archon shards for Energy max.

The Exilus slot goes to [Firewalker], cause Absorb effectively gives us a free [Primed Sure Footed], making us immune to stagger. The only way we can move fast in Absorb with [Assimilate] is by rolling, and [Firewalker] will increase our parkour speed to allow us to roll more smoothly to emulate easy movement. The one downside is that you have to turn off Absorb in order to jump, which sucks. But, all in all, I think this is the best possible [Nyx] build at the moment.

As for equipment to bring, I'd recommend bringing either the [Broken Scepter] for orbs on robotic enemies, or [Dethcube] with [Energy Generator].