I thought that we were all ok to say that the film was NOT about an alien encounter (see the correction here : Lindelof-Bird Project Details [CORRECTION] -- Vulture ).
Anyway, the life of Tesla is full of intersting stories (he did provoke an earthquake in new york, after all).
(and, by the way, back in the early 90's, Terry Gilliam was trying to direct a film about Nikola Tesla)
Other sources persist that it is. So... we'll see.