You can probably save the job.
If you had Versaworks handle the arrangement within the nest job, or if you arranged their order by hand but had Versaworks compact them automatically, then you may be able to recreate the same arrangement get them back.
You want to make sure that the roll width is set to exactly the same width in the new nest job as in the old. If you were using a default preset (for example, by default we use 51.50" for 54" rolls), this may take care of itself. Otherwise, if you have the habit of hitting "Get Media Width" every time, you'll have to make extra certain that it's the same in the new job as in the old. If you have unloaded the media in the meantime or moved the rollers at all, then "Get Media Width" obviously won't return the same result, but the old width might still be in the settings for the individual de-nested jobs.
Usefully, both of the jobs should still have all the same settings as the nest job had. I'd say give it a shot. Just make sure that the layout is the same. What have you got to lose?
If you manually arranged the prints within the nest job, then you are most likely out of luck. Get out that exacto.