United came into the match having won their three previous fixtures and looked on course for a fourth victory when James Wilson opened the scoring.
Collecting a long ball from Demi Mitchell, Wilson raced into opposition territory before firing an angled drive past Arijanet Muric, who had denied him four minutes earlier with a spectacular save.
Muric kept his side in the match when he thwarted Zachary Dearney with another remarkable stop before the break and City took advantage early in the second half when Nmecha met Demeaco Duhaney’s pinpoint cross.
The draw keeps seventh-placed City a point and a place above Ricky Sbragia’s side.
Man Utd: 27 Nov v Everton (A) PL2
Man City: 25 Nov v Spurs (H) PL2