[Steel Charge]: Gives you 18 mod capacity and 60% extra melee damage

[Cunning Drift]: You want some range for [Nidus], but not too much because you will have to wait for his 1 to travel the full distance or to be interrupted by the environment to be able to cast again, so [Cunning Drift] is the perfect range mod, if you want to, you can swap it out for [Power Drift].

Umbral Mods: Maxed out [Intensify] puts you at 181% strength, and Link caps out at 90% [Redirection] at 180% strength when using all three mods.

[Adaptation]: Since [Nidus] is all health, he doesn't get the luxury of shield gating, so you'll need [Adaptation] to help compensate. 90% damage reduction to a specific status for 20 seconds is awesome, especially when linked.

[Primed Continuity]: You need duration to keep Link and Ravenous up for a while for sustain and stack building, and Larva lasts longer so less energy consumed.

[Hunter Adrenaline]: He's only health, so it's kinda silly if you don't use it, it can be substituted with [Rage].

[Insatiable]: Since this build is all about sustain, you need to be able to generate a lot of stacks, so when you spawn in, find a group, larva them, stomp them a few times, wait for them to drop, link one of them, activate grass, larva them again, then stomp more. You do this because your link target also generates a Virulence stomp and does extra damage and generates more stacks, and while your in your grass, you have a 60% chance to generate an extra stack when you make one.

[Abundant Mutation]: [Nidus]' first ability scales in damage depending on how many stacks you have, so getting an extra 200 stacks added to your cap makes this ability really strong in late game, especially in the Steel Path.

Arcane [Guardian]: It's a 15% chance to give 900 armor whenever you take damage. This is a 15% chance per bullet or tick of damage that you take.

Arcane Strike: Since this is a melee meta and we want to attack super fast, Arcane Strike is very good. If for some reason you have Arcane Grace instead of Strike, that'll work too for extra survivability. It's up to personal preference.