The Portuguese manager was appointed this month to replace Erik ten Hag, after leaving Sporting CP.
Nani, who made the same move as a player when he was a youngster, knows that Amorim will need buy-in from the players to be a success.
"It's always difficult to say who the right man is, but I really believe he will do a good job," Nani told A Bola.
"But it doesn't just depend on him and what he will bring to the club.
"It also depends on whether the people who will work with him will be prepared for the demands, to return to being winners. But I believe he will be successful at the club, as he has already shown at Sporting.
"Of course, it's not just a matter of arriving and changing players overnight, I think it takes time. He will work hard and will show that he was a good appointment."