Chadli is thought to have agreed terms on a five-year contract at Tottenham, with the Dutch club receiving around £7m for the player.
The winger will link up with fellow Belgium international stars Mousa Dembele and Jan Vertonghen at Spurs.
A Tottenham statement read: "We are delighted to announce that we have reached agreement with FC Twente for the transfer of Nacer Chadli.
"Subject to personal terms and medical, the Belgian international winger will join up with the squad for pre-season training in Hong Kong."
Chadli scored at his new home ground in the Champions League when Tottenham and Twente were drawn together in the group stages, three years ago.
Swansea and Aston Villa were also interested in Chadli, who has dual citizenship and played for Morocco in a friendly before representing the country of his birth.