The attacking midfielder has caught the eye after excellent performances for the lower league club, and was linked to a raft of Premier League sides including Arsenal, Chelsea and Everton.
However, the Red Devils have sown up a deal for the 18-year-old, who scored in the League Two playoff final against Cheltenham for Stoke a month ago.
The deal is believed to worth as much as £6 million, and Sir Alex Ferguson is delighted that the youngster has completed his move to Old Trafford.
“We have scouted Nick for months now,” the Scot told the club’s official website.
“He is an exceptional talent and has been schooled well at Crewe.
“I’m delighted he has chosen to come to United. He has a lot to offer and we are all looking forward to working with him.”
The England under-18 star has admitted that moving to the Premier League giants is a dream, and he is looking forward to getting started at his new club.
“It really is a dream come true to be signing for Manchester United. I have had a great time at Crewe and I would like to thank them for helping me to develop as a player over the past 13 years.
“I’m excited about continuing my development with Sir Alex and the world-class players in the squad. The thought of making the step up to the Premier League next season is an exciting prospect. I can’t wait to get started,” he concluded.
By Gareth McKnight