Nilathak Maps
The original guide located Here. Full Credits on the guy who made it.
Act 5 Nilathak Boss maps are not so random. There are 3 ways to find him but you must found the way point.
so from way point "Halls of Pain":
Way 1
Way 2
Way 3
And after you found the "To The Halls of Vaught" crypt and go in there are 4 ways to find Nilathak. The ways have some specific marks which tell you where is Nila.
Follow the images:
Symbol 1
Symbol 2
Symbol 3
Symbol 4
That's it :). Just Be careful there!!!