According to the search results, Nobara dies in Jujutsu Kaisen Chapter 126, titled "The Shibuya Incident, Part 43". She was killed during the battle between Yuji and Mahito, where she tries to save Yuji but Mahito kills her. Her death began in Chapter 125, titled "A Story About That Girl," after she recalled the past. Mahito kills her with "plain and simple" physical trauma to her skull. While there are some theories and discussions about her possible return or resurrection, it has been confirmed in Jujutsu Kaisen Chapter 211 that she has been replaced by a newer character, Hana.