Hi Wing,
There is a "Field guide to the Birds of Nepal" by R.Grimmet, C.Inskipp and T.Inskipp, published by Helm in the UK.
I think the plates are adapted from "
ocket guide to the Birds of the Indian Subcontinent" by the same authors.
Hong Kong Bookshops can be disappointing when you're trying to get field guides - perhaps Amazon or similar online service will have these ?
Or follow Captain's suggestion and try to get one in Nepal.
Rgds
John