The two sides were the last teams to be drawn on Wednesday evening, and the Dons chief was delighted to be paired with the 20-time English champions.
He told Sky Sports News: "It's going to be the biggest game in the club's history and what a great time to get them. It's going to be a new-look United, the world will be looking at it and we can't wait to welcome them to Milton Keynes.
"We were just waiting and waiting and right at the end [the draw read] MK Dons at home, and at that point we knew it was Manchester United.
"I am sure all the Manchester United fans that come to Milton Keynes will have a fantastic night and enjoy the spectacle. This is one of the biggest clubs in the world coming to our stadium, we can't wait."
MK Dons beat fierce rivals AFC Wimbledon 3-1 on Tuesday to book their place in the draw, while United are in the second round due to their lack of involvement in Europe this coming season.