Powell's £4million move from Crewe was confirmed on Tuesday. The 18-year-old has signed a four-year contract with the Old Trafford outfit and, whilst there has been some suggestion he might be loaned out by Sir Alex Ferguson, so far there has been no confirmation to that effect.
Instead, Powell is likely to join the Red Devils on their pre-season tour of South Africa and China before the new top-flight campaign begins in August, and he said: "It really is a dream come true to be signing for Manchester United. The thought of making the step up to the Premier League next year is an exciting prospect."
He added: "I have had a great time at Crewe and 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. I can't wait to get started."
It remains to be seen whether Powell will be selected in England's squad for this summer's European Under-19 Championships.
However, given his annoyance at the potential disruption caused by the Olympics later this summer, Sir Alex Ferguson would presumably be unimpressed at Powell's absence for a tournament that runs from July 3-15 in Estonia.
Ferguson is delighted with his latest capture, which comes shortly before Paul Pogba's anticipated departure for Juventus.
Born in Crewe, Powell grew up in nearby Sandbach. His promise was spotted at an early age and was just 16 when he made his senior debut. Powell's last appearance for Crewe came in the npower League Two play-off final at Wembley in May when he scored in the victory over Cheltenham.
"We have scouted Nick for months now," said Ferguson. "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."