HITC Sport understands Foxes are confident over work permit
The teenager only made his first-team debut for Genk last year, originally at centre-half, but he has emerged as a defensive midifelder in the past 12-months, although he can almost play anywhere in defence or midfield.
Now the 19-year-old is set to become Leicester's first signing of 2017, as he will arrive at the King Power Stadium when the transfer window re-opens in the New Year, subject to a work permit.
Ndidi does not have an EU citizenship so would not automatically qualify to play in England, but given the deal is worth £15million there will be little issue in him being granted access to play in the Premier League.
Ndidi is a full Nigerian international with two caps to his name, and he was also named in the preliminary squad for their Olympics, but he did not make the final cut.
Leicester have been looking for extra cover in defensive midfield with the team still struggling to cope with the loss of N'Golo Kante - who left for Chelsea in the summer - and Claudio Ranieri asked wanted another player capable of playing that role.
Leicester are expected to announ ce the conclusion of the deal in the coming days, but a source close to the deal confirmed to HITC Sports: "Everything is done, Genk are happy to have this finalised before Christmas - as are Leicester as there was some interest emanating from other English clubs."
HITC Sport understands that Championship leaders Newcastle United did have a strong interest in Ndidi, through chief scout Graham Carr, but they did not see his value beyond £10million.