Normally, Nico has quite an abrasive personality, but when she takes on her alternate personality, she becomes a happy, upbeat character who is always smiling, often saying her catchphrase, "Nico Nico Nii!" (にっこにっこにー), accompanied with a pose. She usually thinks a bit highly of herself but, despite that, she is also caring.
A common joke in the series is that she's often ignored by the other members of μ's when she claims that she is the better idol. An example of her trying to make the others believe she is the better idol is in Season 1 Episode 10, when Nico claims that she has a personal chef like Maki and has never cooked before. Kotori falls for the lie unknowingly. However, she accidentally forgot about her lie when it was dinner time, and ended up cooking for everyone to reveal the truth.
Nico often gets annoyed with the former student council president, Eli Ayase, for taking away the spotlight from her with her beauty and maturity.