The Portugal star has ruled Arsenal and Manchester City out of the running. United are top at Christmas despite not playing their best football this season.
Nani, 24, said: "I no longer see anybody winning the Premier League outside of Manchester United or Chelsea. Hopefully it will be United."
The winger has enjoyed a productive year at Old Trafford, finally shining in the absence of compatriot Cristiano Ronaldo.
All the attention
He said: "It is easier for me to stand out now that Cristiano Ronaldo has left. He is a fantastic player who got all the attention and deservedly so. I loved playing alongside him and we got on well."
"But it is also true that when he left it freed up space for other players to shine. I saw an opportunity to demonstrate my qualities and to show the people here what I can do," he added.
"I know I can become a better player and my aim now is to get on the list of nominees for next year's Ballon d'Or — the world player of the year prize."
