Osimhen has asked Lille to end negotiations with other clubs, leaving Napoli in the clear to sign him.
The Ligue 1 side want €81m for striker Osimhen, which would make him both their record sale and Napoli’s record buy.
In Italy, the Nigerian international could earn a salary six or seven times higher than his current one.
Negotiations will continue today with Napoli and Lille aiming to agree a deal by Thursday.
Osimhen will travel to Naples for a medical as soon as the clubs agree terms.