According to the site, Nolan will serve as producer on Justice League alongside Man of Steel director Zack Snyder, who may possibly direct the superhero team-up. The plan is said to involve Warner Bros. throwing a boat load of cash Christian Bale's way for him to reprise the role of Batman for a fourth time, where he would line up alongside Henry Cavill's Superman, and render the ending of The Dark Knight Rises completely meaningless in the process. Allegedly, a post-credits sequence in Man of Steel will see Cavill's Superman tracking down Bale's Bruce Wayne, and convincing him to come out of retirement. I guess Joseph Gordon-Levitt's John Blake just wasn't getting the job done in Gotham City...
In an update over at Batman-on-Film, it's suggested that the rumoured project could be a Batman / Superman World's Finest team-up, as opposed to a full-on Justice League movie, while David S. Goyer (Batman Begins, Man of Steel) is expected to pen the screenplay.
Now, I'm sure there are plenty of fans (myself included) excited at the possibility of Christopher Nolan overseeing a DC movie universe, and from a business standpoint, it makes perfect sense for Warner Bros. to bring in Nolan, especially if they're keen to replicate the success that Marvel Studios has had with the Marvel Cinematic Universe. However, despite every virtually site reporting this as fact this morning, I think it's important to take the following with a pinch of salt, until we have confirmation from someone involved in the project.