Gianluigi Buffon, head of delegation with the Italian Football Ffederation (FIGC), told Italy's state broadcaster RAI on Saturday that details of the appointment were being finalised.
"The president and the whole federation have had some busy days but I think that in the end we made the best choice," he said.
Spalletti's sacking came after less than two years in the job, taking charge for the final time in the 2-0 win over Moldova the day after he announced his own dismissal following a 3-0 loss in Norway in Italy's opening World Cup qualifying game.
Gattuso, who made 73 appearances for Italy and was a member of the 2006 World Cup-winning squad, recently left Croatian club Hajduk Split by mutual consent.
He began his managerial career as player coach at Swiss club Sion in 2013 where he finished his playing days after 13 seasons with AC Milan but was fired after winning two of his 10 league games in charge.
Gattuso was appointed as Fiorentina manager in 2021, but 22 days later the club announced they had mutually rescinded the agreement, with reports citing disagreements over transfer strategy.
The 47-year-old will be tasked with getting Italy to next year's World Cup, after they missed out on the last two tournaments, and will begin on the back foot after the humbling loss in Oslo.