Nice finished eighth in the French top flight but are expected to lose Mario Balotelli, who scored 18 league goals last season but is out of contract at the end of the month.
Vieira's assistant coach Christian Lattanzio, performance coach Kristian Wilson and physical performance coach Matt Cook at NY will follow the Frenchman to Nice.
'I'm happy. This is what I was looking for: I will work in good conditions with passionate people, who will support me in the good and bad times. "When I look at the squad, I was very eager, it's very encouraging".
After winning three Premier League titles and three FA Cups he joined Juventus for a season as the club topped Serie A but then were stripped of the title and then had four years with Inter Milan each topped with a Serie A crown.
Michel Barnier and Davis Davis talk Brexit 'backstop'
Mr Barnier suggested a border in the middle of the Irish Sea to check goods travelling across it would have to be imposed. After the meeting, the European Commission published its initial analysis of the British customs plan.