This is the Nightfall equivalent of the invincimonk , its pretty easy to set up. Same as the invincimonk u need 5 superior runes ( they can be anything but a superior scythe mastery one is required) and a set of armor( low level one is fine, anything gets through protective spirit , you WILL die). The skills are:
1.Protective Spirit
2.Mystic Regeneration(best if unlock from Priest of Balthazarand buy it)
3.Mystic Vigor
4.Eremite's Attack
5.Mystic Sweep
6.Reaper's Sweep(Elite)
7.Essence Bond
8.Balthazar's Spirit

The attributes are:
Scythe Mastery - 14
Wind Prayers - 3
Earth Prayers - 13
Mysticism - 10

With 5 enchantments on you , you get + 20 health regeneration which should be enough for farming (This is WAY more effective with 15%dp - You will only have 58 health)

If you only own Nightfall , use Zealous Vow as the Elite and replace the 3 extra slots with utility skills eg. Lyssa's Assasult, Whirling Charge etc.)

The Equipment is a customized scythe with a guided by fate inscrïption (or equivalent) for groups and a zealous scythe for single foes.

Stay away from mobs with heavy degen and enchant removal. It is possible to go to the underworld with this build but its risky and requires a LOT of concentration.