It would be a wonderful move for Chelsea of course. But how can they do this now? The transfer window isn't open anymore. If you mean they can do this in January I don't think so. Napoli would never let Osimhen go in the middle of the season. There is no way Osimhen being keen on doing so either.

Besides I'm doubtful about Osimhen to join Chelsea even if he becomes willing to leave Napoli soon. Chelsea can give a lot of money to him for sure but they aren't a successful team these days. Osimhen would rather stay at Napoli whose condition is much better I think.

As far as I know Napoli are working on an extension of his contract on one hand now.