I never used the nihilak dynasty, but it seems sound to me. Maybe take a cryptek with a canoptek cloack instead of a lord ? Since you won't have much mobility, a cryptek would help you have more staying power on the table.
I like the idea behind grabbing a Cryptek normally.
However, right now, more likely than not the lord is going to use Destroyers (after they get My Will Be Done) to Veil of Darkness into an optimal position to fire, as a cheaper throw-away HQ
. The Overlord needs to stick to the immortals to keep them fearless.
I suppose if the destroyers don't die and have to reanimate, the Cryptek can pal around with them. Good call.