According to Flashscore, the 26-year-old forward joins the Portuguese champions for the remainder of the season, with a non-mandatory purchase option reportedly set at 8 million euros plus performance-related bonuses.
Moffi touched down in Porto on Thursday and attended the Dragons' 3-1 victory over Rangers at Estadio do Dragao, marking his first taste of life in his new surroundings.
He will wear the number 29 shirt and is already familiar with the stadium, having featured for Nice in their 3-0 Champions League defeat there last November.
The Nigerian striker, born in Calabar near the Cameroonian border, comes from a footballing family. His father, Leo Moffi, was a goalkeeper who played in Brazil for Vasco da Gama.
Moffi left Nigeria at 17 for the Buckswood Football Academy in England before making his professional debut in Lithuania with Zalgiris Kaunas and FK Riteriai. His prolific scoring - 20 goals in 21 Lithuanian league matches - earned him a move to Belgium's Kortrijk and later to French side Lorient, where he made an immediate impact.
The forward's performances in France led to a call-up for the Nigerian national team in 2021, and he has since earned six caps for the Super Eagles. While at Nice, he scored 20 goals across competitions and provided six assists under coach Francesco Farioli, playing alongside Pablo Rosario.
Porto will hope the forward can translate his Ligue 1 form to the Primeira Liga, providing goals and creativity in the Dragons' attack as they compete domestically and in Europe.
With his physical presence, technical ability, and proven scoring record, Moffi is expected to be a key figure for Porto as they push toward the title and their European ambitions this season.