Invulnerable - Nightblade Build PvE - ESO

Max armor + both protections = 65% damage resistance

Meditate + Deliberation = +30% damage resistance, theoretically 95%

Light of Cyrodiil = +15% damage resistance while channeling, theoretically 110%

Snow Treaders used in hopes of preventing interrupts. Could use Oakensoul alternatively. Or Cryptcannon Vestments to give your Ultimate Points to allies. Or Spaulder of Ruin as another Aura.

Mages Guild's Radiant Magelight will prevent you from getting stunned by Nightblades for the most part

Temporal Guard and Revealing Flare are your source of Major and Minor Protection

I recommend an Aura set as your secondary set to aid your allies.

Such as Beckoning Steel, reducing damage from projectiles by 10%.

Hiti's Hearth might be beneficial if Mend Wounds procs Deliberation. Of course, if you took a little damage, Meditate to heal and then summon the healing aura from the set.

In case it doesn't fully protect, and you like PvP, Buffer of the Swift, though light armor, grants 10% flat damage resistance against players. Could also help when you aren't able to channel as much.

Blessing of Potentates 2pc is 3% reduced damage from players, if you really want to ensure that.

Defending Traits (weapon), Nirnhoned Traits (Armor and Shield), Protective Traits (Jewelry), to maximize armor. 

Bulwark CP + Frost Staff or Shield = 1900 more armor.