dont think its possible solo, u can take on the aatxe using a spoil victor build, or riposte build. I wouldnt really recomend either though, killing the aatxe is easy with the spoil victor build but nightmares are such a pain for 55 monks.
sample:
(normal mode)
55er mo/me
*use illusion of Haste to lure grasps and run to icewastes
*use visages to prevent interrupts and energy steal from grasps and prevent soj from smites
well, ive got an idea. DONT take quest as u enter the UW.
use illusion of haste, and run to groups of 3 aatxes, and run back (will all monk enchants on), the aatxes break aggro, but the nightmares still rend and they die. now u can take the quest
Also they rend IoH and you get crippled, then the Aatxe think "what the hell I'll chase that dumb-ass crippled monk with 55 health and no protection"
Better is to get rended and run to a ghost. Recast everything with a nice meaty aatxe 2 inches from your face, then casually waltz out from behind the ghost when you're ready and do your thing
I am not sure but we might get ele sec and take a air spell as nightmares has low armor and cast it n them and wathc them die before they rend our enchantments:P