Cripes. If this is true, the metric tonnage of money that just got dumped on Nolan would beggar the imagination. As for how it would work, I'm seriously on the fence. To my mind, Batman only works in a world without the super-human. That's why Nolan's movies worked so well for me, because it was a world of heightened but familiar reality. Alien invaders and Superman just don't fit into that world. Even the two most useless Avengers did more ridiculously super-human stunts than Bale's Batman on his best day.
I guess that's why I'm not really a fan of the JL movie concept in general, regardless of Nolan/Bale's involvement.