Mikan is a local product of the area where Love Live! Sunshine!! is set and has been seen in the TV anime series many times, including with Chika dressing up as the fruit.
Inami, on the other hand, refutes this and claims that Chika’s color is actually mikan “because mikan is the local color!”
In Love Live! Sunshine!! TV anime, Chika’s favorite food is mikan, with her official color being orange.