E. Rossoni considers that the surname has a Greek or Greco-Albanian origin, and derives it from the Italian adaptation of the Greek name Nikolìs, a popular pronunciation of Nikòlaos, the equivalent of the Italian Nicola. He places it as proper to the Salento area —that is, the southernmost zone of the region of Puglia, in southern Italy—, with a presence at Erchie and San Pancrazio Salentino in the Brindisi area, at Taranto, and at Corsano, Lecce, San Pietro in Lama, Trepuzzi and Cavallino in the Lecce area.

F. De Laurentiis, by contrast, places it in Tuscany and links it also to the name Nicola, derived from the Latin Nicolau(m), which in turn goes back to the Greek Nikólaos, interpreted as "victorious among the people", from níkē ("victory") and laós ("people"). De Laurentiis notes that in Italian there existed a form closer to the Greek original, Nicolào, from which Nicolò derived, while Nicola appears to be a later adaptation based on the Greek accent.

According to G. Rohlfs, it is a surname of Greco-Byzantine origin, present in Lucania (Melfi) and in the Salento. From the Greek name Nikolís (Νικολῆς), a form of Nicholas. It reflects the Byzantine presence in southern Italy. It may lose the grave accent in Argentina (Nicoli).