[Nekros] is usually a loot boosting frame but he can utilize his flexible builds to run offensive and defensive options to deal with various content. We subsume a buff to give him damage potential without relying entirely on Terrify's armor stripping.
Nourish, Smite, and Shock all increase the elemental damage of your weapons and even some of your abilities. This lets you save a mod slot or two on your other builds in your loadout. Nourish is the easiest to slot in as it doesn't require an augment but you can use the other two by replacing [Despoil] or [Augur Message].
This build works with damage buffing abilities like Xata's Whisper, Roar, or Eclipse. It even works with hybrid defensive/offensive options like Elemental Ward or Warcry. We don't really need those buffs to kill enemies but they can help you and your team to run unconventional or off-meta weapons.
[Enemy Radar] mods help you and your team to track down enemies. It can be swapped to any other aura to best suit the mission you're playing.
[Health Conversion] can be replaced with [Rolling Guard] for greater consistency against higher level content.
[Mobilize] is a decent movement bonus and there isn't many other things that will fit into the slot in this polarity configuration.
[Augur Message] is a flex mod that can be replaced with any of the augur set mods as you see fit.
Arcane [Guardian] significantly increases your survivability against general content. It can be replaced with any other arcane to suit your playstyle.