• Chloë Grace Moretz as Nimona, a shapeshifter who takes the appearance of a young woman. She insists on being the sidekick to Ballister Boldheart.
• Riz Ahmed as Ballister Boldheart, a former knight for the Institution who was kicked out when he was accused of murdering Queen Valerin.
• Eugene Lee Yang as Ambrosius Goldenloin, the champion knight of the Institution, direct descendant of Gloreth, and Ballister's boyfriend.
• Frances Conroy as the Director
• Lorraine Toussaint as Queen Valerin
• Beck Bennett as Sir Thoddeus "Todd" Sureblade
• RuPaul Charles as Nate Knight
• Indya Moore as Alamzapam Davis
• Julio Torres as Diego the Squire
• Sarah Sherman as Coriander Cavaverish
• Karen Ryan [de] as Gloreth. Ryan also voices a knight version of herself, as well as providing additional voices.
• Cindy Slattery as Syntheya - voice of the Kingdom. Slattery also provides additional voices.
• Sommersill Tarabek as an Institute Analyst. Tarabek also provides additional voices.
• Lylianna Eugene as Patience. Eugene also provides additional voices.
Other members of the production crew who voice knight versions of themselves include directors Nick Bruno and Troy Quane, Julie Zackary, Christopher Campbell, and Randy Trager; Bruno, Quane, Zackary, and Trager also provide additional voices, alongside Wesley Turner. Bruno's sons, Jarrett (who voiced young Walter Beckett from Bruno and Quane's Spies in Disguise) and Jake, voice the kids who play a board game in a commercial as well as provide additional voices, and Taryn Bruno voices a concerned citizen; Trager's relative Sadie also voices a concerned citizen, while Sebastian Trager voices the Danks Kid. Maurissa Horwitz—who also provides additional voices—and former Blue Sky editor Tim Nordquist voice the zombies in a movie Nimona and Ballister watch.

Nimona creator ND Stevenson, who also served as a co-producer and additional screenplay material for the film, has a voice cameo as Kwispy Dragon, a cartoon cereal mascot.

In June 2015, 20th Century Fox Animation acquired the rights for an animated feature film adaptation of Nimona, a webcomic by ND Stevenson. Patrick Osborne was set to direct, from a screenplay by Marc Haimes.

The film was to be produced by Fox's former subsidiary, Blue Sky Studios, alongside Vertigo Entertainment. In June 2017, 20th Century Fox scheduled Nimona to be released on February 14, 2020.

In March 2019, The Walt Disney Company completed its acquisition of Fox, then in May 2019, the film was delayed to March 5, 2021. In November 2019, the film was delayed again to January 14, 2022. Through 2020 there was word that the film would be released in 2022, Stevenson stated in June 2020 that the film was still happening, and said the same in an August 2020 podcast. In August of that same year, Den of Geek reported that the animated film was still scheduled to be released in 2022, but gave no further details, with Deadline reporting the same in October.

Osborne would depart the film by March 2020, and after his departure, Nick Bruno and Troy Quane were brought on in to work on the story after directing Blue Sky's previous film Spies in Disguise (2019). Production would be done remotely during the COVID-19 pandemic.
On February 9, 2021, Disney announced it was closing down Blue Sky Studios, and that production of the film was cancelled. Following the announcement, Stevenson said it was a "sad day" and that he wished the best for everyone who worked at Blue Sky Studios, while Osborne said he was "truly heartbroken" that the studio was closing its doors. Webcomics commenter Gary Tyrrell criticized the decision, saying, "Disney could have allowed a very different kind of young heroine... I mourn for those who would have found a vision of themselves in an animated version". Anonymous staffers at Blue Sky interviewed by Business Insider bemoaned the cancellation of the film, calling it "heartbreaking", arguing that the film "didn't look like anything else in the animated world", and saying that they believe it will never "be completed and released." The film was set to be the first use of Blue Sky's Conduit, a system that allowed artists to "find, track, version and quality control their work." Had it been made, it would have been Blue Sky's first film with LGBTQ representation, as a few staffers confirmed to BuzzFeed News that the film had an "I love you" scene between Ballister Blackheart and Ambrosius Goldenloin.

One staffer stated that before being canceled, the film was "on track" to being finished by October 2021. A former animator at Blue Sky, Rich Fournier, stated that the studio was "very ver…

Read more on Wikipedia

Nimona was originally scheduled to be released in theaters on February 14, 2020, by Walt Disney Studios Motion Pictures through their 20th Century Studios banner, but it was delayed multiple times to March 5, 2021, and then for January 14, 2022. The film was pulled from Disney's release schedule and canceled after the closure of Blue Sky Studios on April 10, 2021. It was revived by Annapurna Pictures with Netflix handling the distribution and was scheduled for a summer 2023 release. The movie premiered at the Annecy International Animation Film Festival on June 14, 2023. The film received early screenings at select theatres on June 23 and 24, and released digitally on Netflix on June 30.

On February 19, 2024, Netflix released the entire film onto YouTube, and the video was privated after a week.