What I think is J-2 visa holder does not file for waiver separately. He/she is solely dependent on the waiver status of the J-1 who is the primary J visa holder. If the husband is Nepali and is eligible for waiver, then her husband should file for it. If husband's waiver is accepted, then J-2 waiver is automatically accepted.
I am not a lawyer. I am sharing only my personal experience and knowledge.