Seems like it's Pfister who suggested that Nolan should meet Bale.
During Saturday’s ‘Kodak Focus’ LAFF session, the audience also had a chance to view 35mm prints of The Dark Knight Rises trailer, as well as reels of Pfister's work on Nolan’s Insomnia (2002) and Inception (2010), and Lisa Cholodenko’s Laurel Canyon (2002), which starred Nolan’s Batman Christian Bale.
Pfister recalled that during post-production on Insomnia, he mentioned to Nolan that Bale was “wonderful” in Laurel Canyon, and suggested that the director and actor meet. “They did, clearly,” Pfister said.