Chirivella arrives at the Ligue 1 club on a free transfer after he rejected a new contract offer at Anfield.
He has signed a three-year contract that will keep him at the Stade de la Beaujoire until 2023.
The 22-year-old has been expected to join Nantes for over a month, but is finally a player of Les Canaris.
A former Valencia youth player, Chirivella joined Liverpool in 2013 and made 10 appearances in total for them.
However, after two loan spells to the Netherlands, Chirivella decided to move on in search of regular football.
Chirivella, who was announced as a Nantes player in a live Facebook video, will wear the number five shirt.