This is a pretty major problem and excludes "honest" low level guilds from competing with "alt" guilds. No average level 60 player stands a chance against a level 60 player backed by a level 200 doc, whether they are attacking or defending.
The simple solution is to put in a PvP level range check for friendly nanos just like for hostile nanos, but only when in a PvP zone. If that level 200 doc tries to heal someone in a PvP zone or in a PvP fight, they must fall within their targets PvP range, or they're SOL.
Very easy and it will let everyone enjoy the Notum Wars equally, regardless of level.