Chadli, who was born in the Belgian town of Liege, raised Belgian eyebrows when was named in a Morocco squad to face Northern Ireland in a friendly in November 2010. He went on to play, and was named man of the match.
The 21-year-old later met with Belgian federation officials and earlier this week annonced on his website he had chosen to play for the Red Devils.
Goalkeepers: Silvio Proto (Anderlecht), Jean-Francois Gillet (Bari/ITA), Simon Mignolet (Sunderland/ENG)
Defenders: Toby Alderweireld (Ajax/NED), Laurent Ciman (Standard Liege), Vincent Kompany (Manchester City/ENG), Nicolas Lombaerts (Zenith St-Petersburg/RUS), Sebastien Pocognoli (Standard Liege), Timmy Simons (Nuremberg/GER), Daniel Van Buyten (Bayern Munich/GER)
Midfielders: Marouane Fellaini (Everton/ENG), Guillaume Gillet (Anderlecht), Jonathan Legear (Anderlecht), Jelle Van Damme (Standard Liege), Jan Vertonghen (Ajax/NED), Axel Witsel (Standard Liege)
Strikers: Nacer Chadli (FC Twente/NED), Moussa Dembele (Fulham/ENG), Eden Hazard (Lille/FRA), Romelu Lukaku (Anderlecht), Marvin Ogunjimi (RC Genk), Bjorn Vleminckx (NEC Nijmegen/NED), Jelle Vossen (RC Genk)