So your job is with a proper POD explain how under one of the principalities at the time under various dynasties, could have united Nepal and created a North Indian Empire or Himalayan Empire (Nepal Sikkim Kumaon, Garhwal, Bhutan, Tibet) etc.
With a North Indian empire, i think it’d be difficult to keep a specifically Nepali core, and I think that could only happen if the empire was comprised of substantial territories south and north of the Himalayas so it can keep its centre in the region linking these areas.
