The Portuguese is hot favourite to replace Louis van Gaal, who just won the FA Cup last Saturday.
Mourinho is believed to have agreed a deal and will be confirmed this week.
Despite the success he has achieved in his career, Mourinho has never spent more than three seasons at a club and Neville insists the cycle will repeat itself at Old Trafford.
“I can’t see him staying too long at Man United, maybe two or three years, that seems to be his shelf life at a football club,” Neville told BBC Five Live’s Sportsweek programme.
“When Jose finishes at a club it tends to be a pattern where he falls out with a few players, he gets disgruntled and the team dips.
“It happened at Chelsea, it certainly happened at Real Madrid where there were rumours he fell out with a few players.
“It’s a pattern with Jose, he comes into a club, he gets success but he doesn’t stay for too long.”