Mourinho has criticised his own squad and board with United struggling during their pre-season tour of America.
They are yet to win a game in 90 minutes and were thrashed 4-1 by rivals Liverpool at the weekend.
Mourinho recently criticised his board, including vice-chairman Ed Woodward, when he said: “I would like two more players. I don’t think I’m going to have two. I think it’s possible I’m going to have one.
“I gave my club a list of five names a few months ago. I wait to see if it’s possible to have one of these players.”
Manchester United have signed Fred, Diogo Dalot and Lee Grant this summer with many players still to return to training following the World Cup.
But former Liverpool ace Nicol believes Mourinho will struggle to get any more new faces in this summer, and he only has himself to blame.
“He could give Woodward 100 targets and maybe none of them would want to go to Manchester United at the moment,” Nicol told ESPN FC.
“Clearly, if you’re that good, you’re not going to have just one option.
“If you’re that good, do you go to a place where there seems to be turmoil?
“You’ve got a manager that doesn’t want to smile and there are problems with the players and manager.
“As experienced, as clever as Mourinho is, he is turning every person in football off of himself and Manchester United.
“If you have a choice, do you go to Liverpool, Manchester City or Manchester United? Guess who is bottom of the list?
“There are two teams on the up – they’re Liverpool and City. What are United doing right now? They’re in no man’s land.”
Anthony Martial is one of United’s stars who has come in for criticism from Mourinho with the boss unhappy at the Frenchman returning home for the birth of his child.
The 22-year-old has been linked with a move to Chelsea and Tottenham while it has also been claimed that PSG rejected the chance to sign him.
Gareth Bale was touted as a potential replacement for Martial though the Welshman now seems set to remain at Real Madrid.
United’s pre-season tour of the US ends against Real in Miami on Wednesday (1.05am).