Naisu is a term, used in gaming, synonymously to “nice”.
It is mostly utilized by professional gamers as an alternative to the mainstream “gg”.
The term is said to be used to imitate Asian players’ accent, when saying the word “nice”.
It is unclear, whether it was Japanese players or Koreans, other tried to imitate.
The most likely origin comes from the early 2000’s when players from South Korea dominated gaming scenes, like Starcraft, Warcraft and later DOTA.
The sheer number of players, who were Korean, as well as the common proficiency displayed across the nation, had led to the expression being adopted in high gamer circles, especially professionals, who were no doubt influenced by the people of the far eastern peninsula.
In the second half of the 2000’s people were more and more familiar with the term, and this was but the mere beginning.
This, and the fact that Urban Dictionary had uploaded an entry on Naisu in 2010 led to the term being adopted by several people, within and without of the gaming community.