Nichosi is a popular meme that originated on the site pikabu.ru and received a powerful promotion on April 1, 2015, when social network VKontakte for every click "like" gave out a funny smile signed by the word "nichosi". Since then, the word "nichosi" quickly scattered on the Internet and even went offline, where it is used, for example, in advertising campaigns, various "creative" comrades.
In general, "nichosi" is just a warped phrase "wow" expressing an extreme degree of surprise. The stress in the word "nichosi" is, as you know, put on the letter "o".
Nichosi is in the list: Slang