João Nuno Duarte Viana (born 13 January 1992) is a Portuguese professional footballer who plays for Swiss club FC Stade Nyonnais as a right back.
Born in Maia, Porto District, Viana played for three clubs as a youth, including Boavista F.C.
In 2011–12 he made his senior debuts with C.D.
Viana appeared in his first professional game on 7 August 2011, starting against F.C.
Penafiel in the season's League Cup.