File Photo: Nigeria striker Moffi. AFP
Moffi, 23, has signed for Nice initially on loan until the end of the season when the transfer will become permanent with the striker signing a contract to 2027.
Different sources say Nice will pay a fee of 25 million euros ($27.1m) plus a possible five million euros more in bonuses, making Moffi their record signing.
Moffi, who used to play in Lithuania and Belgium, has scored 12 goals in Ligue 1 this season, a tally bettered only by Kylian Mbappe, who has 13 for Paris Saint-Germain.
He had also been a target in the January window for Marseille and clubs in the English Premier League.
His departure from Lorient follows that of Dango Ouattara, the Burkina Faso winger who was sold to Bournemouth for a reported 27 million euros.
Moffi's signing is a statement of intent by Nice, who currently lie in mid-table in Ligue 1 but have ambitions of challenging at the top of the standings under their owners Ineos, the group chaired by Monaco-based British petrochemicals billionaire Jim Ratcliffe who bought the club in 2019.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)