With coach Marco Baroni backing the move, Toro are now a step away from signing Ngonge this week.
A verbal agreement has been in place with the player for some time, with a contract running until June 2029 now settled.
Negotiations with Napoli, however, are continuing, and while the terms have been agreed upon, method of payment is yet to be settled.
The deal is developing on the basis of a €1m loan, with an option to buy set at €7m. Torino would like the right to buy, while Napoli is pushing for an obligation to buy at the end of the upcoming season.