The phrase comes from Love Live School Idol Project, where Nico Yazawa, a member of the school idol group μ's, uses Nico Nico Nii as her signature catchphrase and self introduction. Her delivery and hand gesture made the line one of the most quoted moments from the anime, spreading through fan edits, cosplay videos, and anime meme communities. Short clips of the catchphrase were later shared widely on soundboards and social platforms, where it remains a shorthand for cute, confident idol energy.