In practice Nuln oil is never (should never be) your last step.
You go over the washed parts with your base color to restore highlights. You may even add some white for another highlight pass, and so on until you are satisfied with the contrast.
This way you recover your initial green without loosing the nuln oil wash effect.
It may not look as you envisioned pre-wash, but it looks really good anyways. Plus, a light dry brush of green to highlight the darker green will POP!
That looks really cool!
Nothing stopping you from doing a green highlight after. I usually add highlights after drenching my models in wash/shade
In practice Nuln oil is never (should never be) your last step. You go over the washed parts with your base color to restore highlights. You may even add some white for another highlight pass, and so on until you are satisfied with the contrast. This way you recover your initial green without loosing the nuln oil wash effect.