Nasatya Ashvin is the mythological father of Nakula, the fourth of the 5 Pandava brothers and the twin of Sahadeva in the Mahabharata epic in Indian Mythology. When Kunti and the Pandavas go to Hastinapura, Nakula receives archery and sword training under Drona's supervision. Thanks to his success, he gets the title of Maharathi. Nakula is also a good horse keeper, astrologer and Ayurveda expert.

He had a son named Satanika from Draupadi, who was the joint wife of Nakula with his brothers, and a son named Niramitra with the Khedi princess Karenumati, whom he later married.

Nakula Rajasuya ascends to the throne of Nakula Indraprastha, who was sent by Yudhishthira to subdue the western kingdoms for the sacrificial ceremony. Afterwards, Rohitaka, Sairishaka, Mahetta take over the countries and then succeed in subjugating the small tribes named Dasarna, Sivi, Trigarta, Amvashta, Malava, Karnalar, Madhyamakeya, Vattadhana and Utsava-sanketa.

Legend has it that Nakula returns with 10,000 camel-loads of loot after the expedition.

Nakula, who went into exile with his brothers for 13 years after Yudhishthira's loss at the dice game, is kidnapped by Jatasura, who disguised as Brahmin, together with Draupadi, Sahadeva and Yudhishthira. He is rescued by Bhima and during the ensuing melee he manages to kill Nakula Kshemankara, Mahamaha and Suratha.

In the last year of his exile, Nakula, disguised as a groom, works as a horse keeper in the king's stable under the pseudonym of Granthika and Virata.

During the Kurukshetra war, Nakula wants to be the commander of the Pandava army, but prefers Yudhishthira and Arjuna Dhristadyumna. Using a gold-backed red deer gig as a flag on the battlefield, Nakula kills many enemy warriors, including Karna's sons Chitrasena, Sushena and Satyasena, and receives the promotion he deserves at the end of the war.