Nicole greatly resembles her oldest son, Gumball, who is, like her, a cat. She has light blue fur and is somewhere between Gumball and Richard in height. Her head is shaped similarly to Gumball's, except Nicole's whiskers are shorter than her son's, her nose is pink, and she has visible eyelashes. The inside of her mouth is light pink, her tongue is pink, and she has two fang-like teeth that are not always shown.
Her usual outfit consists of a white collared shirt, with a button that symbolizes her workplace, the Rainbow Factory, that has 3 stripes on it (orange, yellow, and green, respectively), and a short, light gray skirt. Like Gumball and Richard, she spends most of her time barefoot.
