According to the Assyrian King List [http://oracc.museum.upenn.edu/riao/kinglists/assyriankinglist/assyriankinglist/index.html#AssurRabi], Enlil-nāṣir son of Aššur-rabi I [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/mittanianhegemony/ashurrabii/index.html], removed his brother Aššur-nādin-aḫḫē I [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/mittanianhegemony/ashurnadinahhei/index.html] from the throne and ruled Assyria for six years. No inscriptions of Enlil-nāṣir II have been found.
Yehonatan Hershkovitz
Yehonatan Hershkovitz, 'Enlil-nāṣir II', The Royal Inscriptions of Assyria online (RIAo) Project, The RIAo Project, a sub-project of MOCCI, 2017 [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/mittanianhegemony/enlilnasirii/]