Someone in the latest sx os release thread in the backups forum posted a supposed way to clean your nand dump by wiping certain areas, I have no idea how legit it is and last time I read the thread nobody else had confirmed or denied it. Generating a fresh nand from prodinfo would also presumably work.
If you've literally never connected your switch online even once, then you should be safe to start again with sparkly fresh empty error logs etc.
If you've literally never connected your switch online even once, then you should be safe to start again with sparkly fresh empty error logs etc.