Chiharu Nitta is a central character in the anime Boys Be..., serving as the primary love interest and childhood friend of the protagonist, Kyoichi Kanzaki. She is a high school student known for her athletic talent, being a dedicated and skilled member of the school's track and field team, where she specializes as a sprinter. Her commitment to the team is a major part of her daily life, often taking precedence over social activities.

In terms of personality, Chiharu is often described as having a tomboyish nature, a direct result of her athletic focus. She is generally portrayed as smart and beautiful, but beneath this capable exterior lies a significant degree of insecurity. She struggles with expressing her own feelings, particularly the romantic ones that begin to surface in her long-standing friendship with Kyoichi. This internal conflict is a key driver of her actions and the misunderstandings that arise between them. At times, this insecurity can manifest as being blind to the feelings of those closest to her, leading to frustration for the people who care about her.

Chiharu's primary role in the story is as the anchor of the main overarching narrative, which focuses on the evolving relationship between her and Kyoichi. Their dynamic, transitioning from comfortable childhood friends to something more complicated and romantic, forms the emotional core of the series. Her motivations are closely tied to her personal goals and her hidden feelings. She is driven to be the best athlete she can be, rigorously training for competitions. Simultaneously, she navigates her growing, confusing feelings for Kyoichi, often unsure how to reconcile her affection with her independent and driven personality.

Chiharu's most significant relationship is, of course, with Kyoichi Kanzaki. They have been friends since childhood, but as they grow older, a romantic tension develops that neither is fully equipped to handle. Her other key relationships are with her two close friends, Aki Mizutani and Yumi Kazama, with whom she discusses the ups and downs of teenage romance. On the track team, she has a senior, Sorimachi, who has a crush on her, though she ultimately rejects his advances. A crucial and controversial relationship in her development is with a mysterious stranger named Yuki. After injuring her ankle and feeling depressed about being unable to train, she meets him and, in a moment of vulnerability, impulsively kisses him. This act is witnessed by Kyoichi, creating a major rift between them that defines a significant portion of the story.

Chiharu undergoes notable development as she confronts her own insecurities and learns to better understand her heart. Her actions with Yuki demonstrate a lapse in judgment born from emotional distress, and the resulting fallout forces her to deal with the consequences of her failure to communicate honestly with Kyoichi. Through the trials of the series, including the long period of estrangement from her best friend, she eventually moves toward a greater understanding of her own feelings and the importance of her bond with Kyoichi, leading to a reconciliation. Her notable abilities lie almost entirely in her athletic prowess as a track runner, a defining characteristic that influences her relationships and her personal identity.