François-Regnault Nitot was born in Paris on 25 February 1779, the son of the jeweller Marie-Étienne Nitot and Marie Catherine Endiger, and was baptised with an uncle, the jeweller Claude Régnault Nitot, as godfather. He worked alongside his father as the house became jeweller to Napoleon. According to French Wikipedia it was François-Regnault who, presenting the tiara Napoleon commissioned in 1805 for Pope Pius VII, met the Empress Joséphine, who then made the Nitots her own jewellers.
Napoleon appointed him to succeed his father on his death in 1809, the year he married Marie Jeanne Agathe Irisson; their son Ferdinand became a general. The house under his direction is credited with the Marie-Louise Diadem of 1810, set with 79 Colombian emeralds and 1,006 diamonds (its emeralds were replaced with Persian turquoise in the 1950s), and the Napoleon Diamond Necklace of 1811 to 1812, with 234 diamonds of about 263 carats, made for the birth of Napoleon II; both are now at the Smithsonian in Washington. An emerald and diamond necklace and earrings made for Marie-Louise in 1810 are in the Louvre. A pair of bracelet-watches commissioned by Eugène de Beauharnais in 1811 placed miniature dials in gold, pearls and emeralds. In 1812, according to French Wikipedia, the house moved to 15 place Vendôme, the future Hôtel Ritz.
A fervent royalist, he withdrew after Napoleon's fall in 1815 and sold the business to his foreman, Jean-Baptiste Fossin. He was mayor of Écharcon from 1817 to 1852, and died at his home on the place Vendôme on 19 January 1853. He is buried at Écharcon.
English and French Wikipedia credit some imperial commissions to father and son jointly, so attribution of individual pieces between them is uncertain.