According to most accounts, Shahnazar killed his half-brother Melik Hovsep Shahnazarian during the disorder following
Nader Shah's death in 1747 and seized control of
Varanda as Melik Shahnazar II. Later, he also killed Hovsep's son Sayi Bek, who had taken refuge with his uncle Melik Allahverdi of Khachen. He sided with the chieftain of nomadic Sarijali branch of the Turkic Javanshir clan,
Panah Ali, accepting his suzerainty and ceding the
fortress of Shushi to him, after which Panah Ali made it the capital of the newfound
Karabakh Khanate. He forced the meliks of
Jraberd and
Gulistan to flee and severely weakened the melik of
Dizak. A truce was reached in 1760 when the meliks were allowed to remain in possession of their lands in return for recognition of Panah as Khan of Karabakh. Shahnazar further consolidated his alliance with the Khans of Karabakh by marrying his daughter Hurizad Khanum off to Panah Ali's son
Ibrahim Khalil Khan. He died in 1792. There is an alternative version of Melik Shahnazar's accession according to which he became ruler by legal means. In 1736, Shahnazar's father Melik Hussein died, and since Shahnazar was a minor, Hussein's brother Mirzabek became Melik of Varanda. In 1743,
Nader Shah of Iran revoked Mirzabek's melikal rights and, through
Melik Yegan's mediation, elevated the twelve-year-old Shahnazar to the throne. Nadir Shah's
firman confirming Shahnazar as melik has survived and is kept at the
Matenadaran in Armenia. In historian Pavel Chobanyan's view, the story of Shahnazar's murder of his brother and usurpation of the throne was invented by Muslim historians such as
Mirza Jamal Javanshir and
Mirza Adigozal Bey, who were seeking to affirm the hereditary rights of the khans of Karabakh and their descendants and discredit those of the Melik-Shahnazarians before the Russian authorities; later, this story was adopted and repeated by Armenian authors. Additionally, there are documents which indicate that Shahnazar's brother Hovsep was still alive when the former was already reigning and that Hovsep died after Shahnazar, thus refuting the information the Shahnazar killed his own brother. ==Legacy and memory==