In my experience,

I had a friend working for American Educational Foundation "FulBright." He attested all my academic documents and sent them via mail. You can find anyone working for the same.

Other option is (may not be true): that there is a Public notory office in BabarMahal, Kathmandu. Send someone with all required IDs to have them notorized. However, I am not sure, if public notory-Nepal will work for the same.

Hope it helps.

Good luck!