The line comes from Nico Yazawa, a member of the school idol group μ's in Love Live! School Idol Project, the anime series that began in 2013. Nico uses Nico Nico Ni as her trademark greeting, pairing the words with a heart-shaped hand gesture, and fans quickly turned the moment into a shorthand for her confident, playful personality. Clips spread through anime edits, reaction videos and soundboards, where the short length and unmistakable rhythm made it easy to reuse. It remains popular because it instantly signals Love Live fandom and cute, self-assured humour in just a few seconds.