If you are contributing less than $56k (a little higher if over 50) across all DC and DB plans, a NQDC likely isn't needed. If more than $56k total contributions is desired, the NQDC likely still makes sense.
I only brought it up as most plans don't allow after-tax contributions and it would be a much cheaper/easier solution if you weren't trying to defer a lot more.
Be aware that after-tax contributions are subject to top-heavy testing, while the NQDC contributions are not.