It could be that the movie just isn’t ready yet, that the script still needs work before things can really go anywhere.
So, while the Nightwing movie isn’t dead, fans shouldn’t be expecting much to happen with it anytime soon.
Chris McKay doesn’t go into any further detail about why we’re going to have to wait.
It could also just be the fact that Warner Bros. doesn’t plan for Nightwing to go into production for a while and so there’s no reason for anything about it to move forward.