Empire magazine conducted and easter egg round up a few days after Man Of Steel was released and there's one that has confirmed that there is an active Batman in this Universe. no.. Not just Bruce Wayne, his superhero alter ego.. The Batman himself is referenced in the Office when Zod first acquires his heat vision. In the Corner somewhere, there's a poster that boldly states
"KEEP CALM AND CALL BATMAN"
Of the easter egg Snyder had this to say
"You might even have to stop the movie to see it but it’s definitely in there. That’s a Double Negative Productions [Easter Egg]. D Neg is the visual effects company here in London that worked on all the Dark Knight movies, and they definitely did that. And [when I saw it], I was like, ‘That’s awesome."
There's more on the original article that even includes a nod to The Hulk! of all things.. go to the link provided for more.. so what do you think? Justice League nods or just fun props?
UPDATED ONE YEAR LATER: I guess DC knew what they were doing the entire time. In addition to the existence of Batman being canon now, other easter eggs have paid off in the form of Star Labs leading to Cyborg, Lex Luthor finally having a physical presence in this universe and hell, some who still believe those whales were a reference to Aquaman are reinforcing this belief with the rumored involment of the character in the film. WB/DC seems to be far ahead in their plans than we think.