I used to run enduring nazgul corruption on standard back on GCCG, and I have a few tips.
I used to focus on
Enquea, ToTo +
Dark Fell About Him with
Lingering Shadow for corruption.
I'd definitely run more of those.
Nertea, Dark Horseman +
Saruman, SoS sets it up nicely, makes it easier to both get
Lingering Shadow on desirable companions and to exhaust them.
I would not be overly focused around the enduring keyword, if you want to win with corruption focus around that.
They Feel the Precious is nice to protect Enquea and Nertea, a Gollum splash can also be invalueable.
Toldea, Black Shadow can also be very helpful in returning key events. Also enables a strong line of
Too Great and Terrible (you gonna want that in competitve expanded).
Winged Mount is also a nice addition, protects key nazgul and protects from clogging.
I ran a mix of Nelya,
ToTo and
Nelya, Third of the Nine Riders as site manipulation is invalueable in expanded.
Ring of Terror is always nice in expanded.
Lemenya, ET also worths consideration. I'd also run
Morgul King over the toli version of WK. You will hardly ever win in expanded with enduring nazgul beatdown.
To summarize it I'd say the key components are: protecting key nazgul and controling the assignment without clogging your hand.