NocXan is a legendary Runeword created by combining a Noc Rune of Ritual and a Xan Rune of Invocation.
How to Create NocXan
You can create NocXan by adding the rare Noc Rune of Ritual and the legendary Xan Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Noc - Inflict a Crowd Control that isn't Slow or Chill. (10)
Xan - Your next Skill cast will be a guaranteed Critical Strike and Overpower. (800)
Overflow
NocXan can not overflow because the Xan Rune does not have an overflow effect.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.