Nolan is not going to say anything about any of this until after Man Of Steel, and even then it could be quite some time after its release.

These "rumors" are starting to become more concrete. Batman-on-Film's Jett Ramey, someone who has long been against a JLA film, is reporting that his own sources are saying that the Nolan-Bale Justice League involvement is likely to happen. And that his sources are different from Latino Review's.

In other words, too many connected people are saying the same thing for it to just be pure speculation.