Valle San Nicolao is a comune (municipality) in the Province of Biella in the Italian region Piedmont, located about northeast of Turin and about northeast of Biella. As of 31 December 2004, it had a population of 1,136 and an area of .
Valle San Nicolao borders the following municipalities: Bioglio, Camandona, Cossato, Pettinengo, Piatto, Piedicavallo, Quaregna, Scopello, Strona, Trivero, Vallanzengo, Valle Mosso.