A Nightwing film, a spin-off of Batman, was in development at DC. However, that doesn't appear to be the case anymore.
According to The Wrap's Umberto Gonzalez, the Batman spin-off film is “dead” at DC. He was responding to an X (formerly Twitter) user who was hoping Chris McKay would still get a chance to direct a Nightwing film.
that project is dead
— Umberto Gonzalez (@elmayimbe) August 22, 2023
Nightwing isn't the first Batman-related project to be canceled by DC. A Batgirl film was scrapped after being in the can.
The character of Nightwing is a Batman side character. Dick Grayson usually assumes the mantle, and he was Batman's partner and sidekick in many iterations in the comics.
While he's been portrayed in various DC animated series, the Nightwing character is yet to get his due in live-action form. Granted, Chris O'Donnell played the role of Dick Grayson in the infamous George Clooney-led Batman & Robin, but he was Robin.
DC is currently in a rebuilding mode. James Gunn and Peter Safran are gearing up to implement their own regime. The DCEU began with Man of Steel in 2013, but the last two holdovers are getting ready to be released before the slate is cleaned. Blue Beetle was just released and has grossed over $40 million to date. Aquaman and the Lost Kingdom is the final film left before Gunn and Safran are able to official kick off their regime.
Granted, perhaps a Nightwing film could be in the cards down the line. James Gunn recently revealed that he hasn't even cast a Batman for his DCU franchise. That feels like the logical first step before even thinking about Nightwing.