Nightblade Tank Build
Nightblade tank builds are exceptional at taking care of themselves with great healing power and amazing sustain options, meaning the healer in your group will be under much less pressure and can focus on keeping the DPS alive. While Nightblade tank builds may provide less in terms of buffs and debuffs, their in-combat efficacy can't be questioned.
Gear Sets
Baron Zaudrus: By slotting Elemental Susceptibility, you can activate Baron Zaudrus by simply using this one free skill once, and you can even spam it for repeated Zaudrus procs, giving your team a nice, steady supply of ultimate. Get this set from The Cauldron.
Drake's Rush: A great set that you can get from Black Drake Villa. When you bash an enemy, you and up to three group members get Major Heroism for a lengthy duration, which is a really nice buff in a PvE meta dominated by ultimate generation. You can get a total of 66% uptime on Major Heroism with this set, which is very high considering the amount of ultimate it produces.
Arkasis' Genius: Another set that synergizes well with the theme of turning your tank into an ultimate battery. Obtained from Stone Garden, Arkasis' Genius will transfer a ton of ultimate to you and some team members every time you use a potion, working perfectly with the Nightblade's Catalyst passive, meaning you can pump out Aggressive Horn more than any other class.
Puncturing Remedy: This is a great two-piece set from Dragonstar Arena that will allow you to bolster your own resistances and heal yourself simply by taunting with Pierce Armour, which you will be doing anyway. This is perfect for taking some pressure off your healer.
Skills
Pierce Armor: This is your primary taunt, allowing you to apply both Major Breach and Minor Breach to the enemy. This also activates the Master's weapons, granting resistances and a heal.
Dark Cloak: Dark Cloak works as both a strong heal if you are standing still and allows you to activate the Shadow Barrier passive, granting Major Resolve.
Mass Hysteria: A potent AoE stun that has the added bonus of applying Major Cowardice to all enemies effected, which is an incredibly powerful debuff.
Mirage: This is a flex slot that will help massively with many fights, allowing you to take significantly less damage from area attacks. You can switch this out if it isn't needed.
Silver Leash: This skill will allow you to control the battlefield by pulling smaller enemies to you, which helps DPS.
Aggressive Horn: Your primary ultimate that adds a ton of damage output to your whole group. Try to use this as often as possible.
Elemental Blockade: This is a great skill with multiple functions. It can snare and root enemies, apply Chilled and Brittle to them, and applies a projectile shield to you and your allies.
Destructive Clench: Destructive Clench is your ranged taunt that has the added benefit of always applying Chilled and Major Maim and immobilizing the enemy.
Elemental Susceptibility: If you aren't under too much pressure, you can spam this to activate the Baron Zaudrus set repeatedly, feeding ultimate to your group consistently.
Refreshing Path: This is a nifty addition that adds a heal over time in an area and also provides a welcome speed boost to your team. You can switch this to something else if you wish, but it is useful.
Leeching Strikes: You should keep this active at all times. If you are careful about your timing, you should weave light attacks into your skills as much as possible, feeding resources back to you. However, just keeping it active will return a big batch of resources to you when the effect ends, which is also useful.
Refreshing Barrier: A great backup ability that will save your group in a tough situation and allow them to keep fighting through tough mechanics.
Champion Points
Ironclad: This grants you a nice boost to your damage mitigation against direct damage attacks, which is one of the most common that you will encounter in PvE.
Enduring Resolve: Damage over time mitigation is very useful, since it counts for single target DoTs and area DoTs. This means that, in many cases, this will stack with Unassailable.
Duellist's Rebuff: Often stacking with Ironclad to further boost your resistance against single target attacks, this is a useful one for tanks in particular, helping to mitigate the heavy damage coming from bosses.
Unassailable: Helping you to stand in stupid for longer, Unassailable will reduce your damage taken from area attacks, helping towards taking the pressure off the healer.
Boundless Vitality: Every bit of health makes a difference, especially in some of the tougher content that The Elder Scrolls Online has to offer. This will help you bump yours up a little more, increasing your survivability.
Fortified: Similar to Boundless Vitality, one can never have enough resistances, and this will add a little extra to boost your survivability so that you can focus more on the task at hand.
Sustained by Suffering: Gaining the ability to regenerate resources faster when you have negative effects on you is just perfect for a tank, making this a smart choice.
Bracing Anchor: As a tank, you don't need to move that much, but you certainly need to block as much as possible, making this a great addition to your toolkit.
Mundus Stone
The Atronach is best suited for tank builds, boosting Magicka Recovery substantially, which is important for keeping up with buffs and subsidiary healing. Stamina can be regained through potions, heavy attacking and group synergy activation.
Food Buff
Tanks benefit especially well from Orzorga's Smoked Bear Haunch, boosting all recoveries along with Max Health as well. However, it is expensive, so if you need a cost-effect option, use the Bewitched Sugar Skulls, which are also very effective.
Race
The best race to use for this build is a Nord for its higher resistances and ultimate regeneration, but Argonians, Imperials and Bretons are also excellent options for their superior survivability and sustain.
Potion
Tri-restoration potions are generally the best for any tank to run, allowing you to manage your resources perfectly. However, when you are dealing with trash mobs and the like, you won't want to waste them, so carry some trash potions around for the parts that aren't very intense.
Mortality
The Undeath passive can be tempting for tanks, but running a Vampire on all but highly specialised and rather inefficient builds is a bad idea. The amount of fire damage found in PvE content, and the high increase to standard skill costs, will make running Vampire on a PvE tank a liability.
Notes
Nightblade occupy a unique niche in tanking, making them very powerful in group dungeons, although they don't get to shine so much in trials scenarios.
One of the big selling points of Nightblades is their ability to generate ultimate incredibly quickly, moreso with the gear choices that we have made. Your role, therefore, in addition to controlling the battlefield, taking all the pain and shrugging it off, is to generate and use your ultimate abilities as much as possible, providing your group with powerful buffs.