Guide:
Really easy Nyx Prime build, made for confronting liches/sisters at any level and its really easy to use since there are only 4 steps once the fight begins:
1. Use Absorb to become completely immune to damage.
2. Use Silence on the lich/sister.
3. Use Physic Bolts on the lich/sister.
4. Aim for its head and kill it.
I recommend using a strong shotgun with this build like a Kuva Hek or Felarx, but if u don't want to use a shotgun, Phenmor and/or Laetum would to the job perfectly. Just make sure they are modded with the damage types that the lich/sister is vulnerable from. In case they do not have any weaknesses mod corrosive, unless they are resistant to it.

Notes on the build:

• The build is most effective if the fight is started with a full energy bar, which can be crafted in the Railjack or gotten along
  the way through Energy Siphon and Zenurik's Wellspring.
• Silence can be subsumed over Mind control or over Chaos, matter of preference. Whatever you choose, the build will work the same.
• The aura mod is very flexible, any aura in the game besides Power Donation and Combat Discipline works, I chose
  Energy Siphon because it will passively increase my energy outside of Absorb.
• Arcane Energize is a must, Arcane Rage is not.
• Boreal's Hatred is flexible for Streamline.
• [Narrow Minded] is at rank 8 so that the range of Silence stays as high as possible(>90% is ideal),but ultimately it doesn't
  matter that much.
• If you want to slot an exilus mod without using any Forma swap [Intensify] for [Augur Secrets] and 1 Crimson Archon Shard
  with +10% Ability Strength, Stretch for Augur Reach(this will affect the range of Silence but it isn't really an issue because
  the lich/sister is the only one who needs to be silenced) or Primed Flow for Flow(the reduction in the energy pool isn't a
  problem the difference here is 183 energy).
• All Archon Shards of your own choosing.
• Primed Sure Footed is useless since Absorb exists.
• For general use, this build is alright but there are better ones.
  I wish you happy hunting tenno.