I am trying to learn Nicaraguan Sign Language (ISN), but I can't seem to find online resources. I don't have anyone to learn from offline, so online is the only way. I am open to different methods (videos, books, etc.); however, if there were any learning games (similar to Duolingo, Memrise, etc.) then that would be better.
Almost four years later, and after having gone to Nicaragua to learn the language, I finally found some online resources. Unfortunately, nearly all of them are in Spanish so it will be very difficult if you try to learn from English. The following videos are on youtube, they were originally produced for television.
The above links were mostly vocabulary-building courses; for a guide to basic grammar try this video:
You can also download the NSL dictionary (it's behind a paywall and all in Spanish, sorry) https://www.scribd.com/doc/51857367/Lenguaje-de-Senas-nicaraguense