It's possible, but it takes some practice. I solo UW with my N/Mo, so I'm in the same boat as you in terms of spells. I find that wanding generally isn't a safe route, because even with a customized max damage wand, only about 70% of the time am I able to kill it in 2 hits.
For the first set of aataxes on the left, I usually just aggro them and use the ghost trick (squeeze yourself between Anson and the other ghost..ask around if you're not sure how), and let the nightmare kill itself by rending my 4 enchants. Then I can take my time recasting them and killing the aataxes.
Generally, you can coax the rest of the nightmares into spawning without aggroing the aataxes after you gain some experience in knowing their usual spawn points. However, there are always the unexpected spawns. What I do do counter this is I always have 4 enchants (including prot spirit) on before aggroing an aataxe group. If a nightmare spawns, I click on it so I can see its status bar and start running away. You can usually run out of the aataxe's range before it finishes casting rend, but if not, because you already had prot spirit cast, you can put it up almost instantly after it's rended. After recasting prot, just keep running until you can shake the aataxes (use ghost trick again if necessary), and reapply your other enchants.
Hope that helped
