I'm a R50 LNC and I can honestly say LNC isn't a viable tank because of damage mitigation and HP (which shouldn't be an issue with enough damage mitigation). However, LNC does have a great advantage enmity (hate) wise due to being able to use enmity actions back to back much faster than any other class with Speed Surge II.

Haven't tried it yet, but I think evasion tank or defense/evasion tank setup would work best with LNC which might be viable at that point, but your going to need a lot of ranked classes. I'd suggest Defender/Defender II + Obsess/Obsess II (1 mob only) + Diversion + Decoy (ARC 36) + Featherfoot + Absorb DEF + Absorb ATK as main actions and maybe some more if that isn't enough.

Get Firm Conviction and Fast Cast traits from CON and THM and Cure III and/or Sacrifice III to help heal for the amount of damage you take and Stygian Spikes/Stygian Spikes II and/or Siphon MP/Siphon MP II so you can spam cures literally back to back when needed.

LNC "might" be a viable tank but it's definitely much more work than GLA, MRD, or PGL and possibly even THM might be more viable although I'm sure it can be done with enough determination and/or a tanking role via jobs if added.