He was married to Abrota, and when she died, Nisos commanded that the Megarian women wear clothes like she had. His daughter Eurynome, with Poseidon, had the famous son Bellerophon. Nisos's other daughter Scylla was responsible for his own death.
Metion, the uncle of Nisos, had seized the throne from Pandion II. However, upon their father's death, Nisos and his brothers (Aegeas, Pallas, and Lykos) returned to Athens and took back control. They drove out the sons of Metion, put Aegeus on the throne, and divided the government in four. Aegeas became king of Athens, and Nisos the King of Megara.
Minos, King of Crete, attacked Nisos's kingdom during a war with Athens over the death of his son Androgeus. Nisos however had a lock of purple hair that kept him safe from harm. Eros caused his daughter Scylla to fall in love with Minos. In one version, Minos tempts Scylla with a golden necklace to betray and kill her father. In another version, she falls in love with Minos from a distance, and after cutting off the purple lock, she presents it to Minos. However, Minos was disgusted with her act, calling her a disgrace. As Minos's ships set sail, Scylla attempts to climb up one of them. But Nisos, who had turned into a sea eagle or osprey, attacks her. His daughter transforms into a bird as well.