It seems hero Nani has emerged as the hero of bilingual and multi lingual films. It doesn't mean that he is acting as the hero in all the language versions of these films. He does the role of a hero in Telugu versions and other language versions hero roles are played by other heroes.Check out the following examples.
EEGA: This movie was simultaneously made in both Telugu and Tamil versions. Tamil movie's name is 'Naan Ee'. Nani played the hero in both the versions of the movie.
ETO VELLIPOYINDI MANASU: This is being made in three languages and they are Telugu, Tamil and Hindi. Nani is doing the hero of Telugu version while Jiiva and Aditya Roy Kapoor are doing the heroes in Tamil and Hindi versions respectively.
NANI-SAMUDRAKHANI MOVIE: Nani and Amala Paul are the star cast of the Telugu version's movie. Jayam Ravi is doing hero in Tamil version. Amala Paul is the heroine of this version as well.