The Senegal international, who arrived at the Stadium of Light last January, was sent on a season-long loan to Eskisehirspor in July but the Turkish side announced on Monday that they had cut his loan short.
N’Diaye will not, however, return to his parent club as Sunderland have already reached an agreement with Betis over a fresh loan deal until the end of the season.
The 23-year-old is expected to arrive in Seville on Tuesday to undertake his medical at Betis but the Spanish side will face a race against time to get the deal rubber-stamped before the close of the window.