Haham Isaac Nieto (1687–1773), was born in Leghorn and taken to London when his father R. David Nieto became haham in 1701. He was appointed to succeed him in 1732, after an interregnum of four years. Nieto held office only until 1741, when he went abroad. Returning to England, he was admitted as a public notary and built up a considerable practice. On the death of Moses Gomes de Mesquita (1688–1751), who had been haham since 1744, Nieto was appointed av bet din (in effect, acting rabbi) of the community, but resigned in 1757 in protest against the appointment to the bet din of Moses Cohen d'Azevedo (1720–1784, haham from 1761). During the controversy over ritual slaughter in London, which began in 1761 through the captious criticisms of Jacob Kimhi, Nieto attacked the bet din so vigorously that the Mahamad ordered that his decisions in matters of Jewish law should thereafter be disregarded. Nieto published a number of sermons in Spanish and Portuguese, of which one appeared also in English (London, 1756) on the occasion of the earthquake of 1756; this was the first Jewish sermon to be published in English. His translations into Spanish of the liturgy for Rosh Ha-Shanah and the Day of Atonement (ibid., 1740) and of the daily prayers (ibid., 1771) were highly regarded for their style. Following his father's example, he also published a series of calendars.
כולל "התחינות והוידוים וסדר עבודה" ופיוטים אחרים ליום כפור, כמנהג הספרדים, עם תרגום לספרדית מאת ר' יצחק נייטו "רב של ק"ק לונדריס".