Ironically, former Blues teammate Vialli also had a spell in charge at Vicarage Road.
"I think it is easier when you work for a club you are fond of," Vialli told the Mirror. "Mourinho is obviously fond of Chelsea and Inter.
"I can see him going back to either club and do very well though I would chose the Premier League. Mourinho is a very strong option and if it did happen, it would be a good thing.
"Having said that, I can see another Italian manager taking over there. We have had four in the last 15 years (Vialli, Claudio Ranieri, Carlo Ancelotti and Roberto Di Matteo) and for some reason, Italian managers tend to do well at Chelsea.
"Maybe Gianfranco Zola could be next if not Mourinho to follow Rafa Benitez. Gus Poyet is another option. Both have got strong feelings for the club and the fans know that and respect that. And if you have been there as a player, it is easier."