He is named only in Irish legend a thousand years after his supposed life as the Pharaoh of the Exodus. Some modern genealogists have speculated that Nactabaeus might have been Necho I or Necho II.

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Another thought about Nactabaeus.... (Covers the other options names for Scota's father's name - same person, although the names are very different depending on the source):

Scota was the daughter of Egyptian Pharaoh Smenkhkare. Smenkhkare was known by several other names and spellings of his own name. These include Smenkhkara, Smenkhkaron, Achencheres or Akenkeres (the Greek form, used in Manetho’s Egyptian King List), Cencheres (the version used by the Christian church-father Eusebius), and Cinciris or Cingeris (from early Gaelic history).

http://www.carothers-carruthers.com/scotlandnamesake

Kheperkare Nakhtnebef, better known with his hellenized name Nectanebo I, was an ancient Egyptian pharaoh, founder of the last native dynasty of Egypt, the thirtieth.

Nectanebo was an army general from Sebennytos, son of an important military officer named Teos (hellenization of the Egyptian name Djedhor). A stele found at Hermopolis[4] provides clues that he came to power by overthrowing, and possibly putting to death, the last pharaoh of the 29th Dynasty Nepherites II.[5] It has been suggested that Nectanebo was assisted in the coup by the Athenian general Chabrias. Nectanebo carried out the coronation ceremony in c. 379/8 BCE in both Sais and Memphis,[6] and shifted the capital from Mendes to Sebennytos.[7]

The relationships between Nectanebo and the pharaohs of the previous dynasty are not entirely clear. He showed little regard for both Nepherites II and his father Achoris, calling the former inept and the latter an usurper.[8][9] He seemed to have had a higher regard for Nepherites I; this king has been considered to be Nectanebo's father or grandfather, although it is now believed that this view was due to a misinterpretation of the Demotic Chronicle.[5] However, it has been suggested that both Achoris and Nectanebo may have been Nepherites I's relatives in some way.[9]

Nectanebo had two known sons: Teos, who was his appointed successor, and Tjahapimu.[5]