I have enjoyed tanking with both a mag and stam NB. The linked build is an endgame trial build, is that what you are planning? Because builds for other content including regular trials can be very different.

For example, a pull is necessary or useful only in certain content, not at all needed in normal or many vet dungeons, many trials. Moreover, adds in many dungeons are specifically set up to be outside pull range. More important IMO is the ranged taunt, which can come from ice staff in intermediate content or instant undaunted rage combined with ice staff taunt in higher.

For normal content and lower vet, neither a pull nor ranged taunt are needed in most cases as long as the team is letting the tank shape the aggro and not preaggroing. Once you get used to how specific mob packs and adds respond, you can have them move into a pile naturally based on your initial aggro. AOE aggro such as from blockade or hail are key on trash packs.

NBs have some strong innate damage reduction from focus and mirage (mirage, focus or another assassin skill is mandatory on NB tank due to the hemorrhage passive) due to so much PvE damage being aoe, good LA healing and resource management with siphoning strikes, so IMO those three and puncture/heroic in S/B are mandatory. There's 5 skills, half your regular skills.

Then you want infused crusher blockade or hail and a hard CC, fear or turn evil, if bow maybe bombard. So there's 7 skills filled. Fear triggers the shadow resists passive, as does refreshing path or dark cloak. I personally prefer path over cloak because it is so useful in speeding up the team between packs/bosses with major expedition (also allows quick escape from fast red preserving stam), and heals across the boss to the dps. I consider refreshing path so generally useful as to be mandatory. Others may find differently. For me that's now 8 skills with either path or cloak.

The last two skills are flex and situational. Ranged taunt, Lotus Fan if no minor vulnerability in team, orb if running without a healer, Vamp drain if a fast ult generation build, silver shards for pull, funnel health for siphon/ult passive spam or more heals, other possibilities.

Ults are WH, tether, bolstering darkness, soul harvest (you will get many killing blow ticks on trash and adds with blockade/hail speeding ult generation if using soul harvest), other possibilities

All the damage mitigation available on a NB tank allows for a bit higher spell/weapon damage or lower health. I did a normal trial the other day and never had to block, allowing constant taunting, repositioning, HA for sustain and being free to cast other things. But you -will- need to block lots of stuff, just less.

My favorite forgiving NB tank that can allow 3dps/1 tank teams or carry pugs is a magicka mitigation tank with Werewolf/Dragonguard/Dead-water/next patch potentates/bloodspawn, or Nightflame set. If you keep all your ult sources running (try to save pots to drink just after you cast bolstering dark), and sneak in a vamp drain or two while others would need to block, you can keep bolstering darkness 30% major protection up on the team constantly, not to mention the gigantic heal synergy of that ult. Not the best for low content because it does little DPS, but a great kind of tank to have around if fake healer, weak healer, no healer, OT trials, all pugs, etc.

NB tank is lots of fun, gl with it.

I am also working on a nightblade tank (magicka primary and for dungeons) and really enjoy it! Right now (at level 30) I use Lotus Fan (Teleport Strike) and Shield Charge as gap closers.

Looking over the Alcast build, I see they recommend 0 Atteibute points in Health — can that be right?! I had thought that tanks always had to put some points in health but does it all come from armor, food and other buffs in this case?

Thank you for all the detailed info, @buttaface !

Wanted to provide an update. I've been able to acquire the complete Ebon Armory set on the body pieces, as well as a medium/light Lord Warden set, and Torug's Pact on the weapons and jewellery.

The weights obviously mean I get full benefit of Undaunted Mettle, and the health bonus has been great for the PuGs I get.

I'm finding the survival to be brilliant, and I'm managing resources much better than I ever did in the DPS role.

In turn, where I was hesitant to run pledge as DPS, in fact I only ran them with my guild... I now suddenly have the confidence to just pick 'em up and do 'em as a tank.

I'm very happy to have made this move, as I am enjoying the game much more now.

This also changes my plans with my DK. I'm now thinking of building him as a character specifically to tackle vMA, because honestly? This NB of mine is coming across as a decent tank already.

I miss my NB sap tank. Best fun I ever had in ESO

Nord
Pot CD jewelry enchants
Vamp w/invig drain
Heroic slash
Frost staff / snb
Torugs + ebony
40/19/19 stat pools

Rotate vamp drain, heroic slash and drain power while using pots on CD for siphoning ult gen passive, on top of being nord will result in the highest warhorn uptime of any tank, and tank almost anything. Just adjust your stat pool and select the appropriate siphoning attacks / inner fire morphs and use dark cloak to absorb tank buster hits. New nb fear is a great aoe control tool in combination with frost blockade.

This build is confirmed to work on every vet dlc dungeon HM and most vet trials.

Edit: forgot to add bloodspawn as well.