The 31-year-old Spaniard had dropped in the Villa Park hierarchy behind Lucas Digne and new recruit Ian Maatsen.
Moreno, who had previously been linked to Forest, signed a £13.2 million contract to join Villa from La Liga team Real Betis in January 2023. This was Unai Emery’s first acquisition.
Last season, he participated in 21 Premier League games as Villa finished fourth and advanced to the Champions League.
“Alex is a player we have had a long-standing interest in so we are naturally all very happy to see him arrive at Nottingham Forest,” stated Ross Wilson, chief football officer of Nottingham Forest.
He adds all of that quality and expertise to our group right now. He has accumulated a great deal of experience in both the Premier League and La Liga.
Meanwhile, it appears that 27-year-old defender Joe Worrall will be leaving Forest. Burnley, a Championship team, is in advanced talks to sign the player.