I bought my copy in the US with a US credit card and have activated and used outside the US many times with no problems.
I have never seen anyone claim Black Magic's servers are doing any sort of geographical check when your install dials home to verify the key.
I would expect the BM web store to refuse to allow a purchase 'In the US' with a Nepal credit card for tax reasons. Steam does a similar check to prevent everyone from saying they live in Argentina a get a better price.
Not sure if Black Magic Hardware is easy to get in Nepal. But if you can get a respectable price on the speed editor ($435 in US) it comes with a free resolve key. So you basically get a great console for $135.
https://www.bhphotovideo.com/c/product/ ... ditor.html