United has only secured one away victory this season, against Liverpool, despite a recent three-match winning run at Old Trafford.
Amorim expects a tough match at the City Ground, noting that Forest has won their last three Premier League encounters against United.
He emphasised the need for United to better control the match environment away from home, anticipating less space to play compared to their recent Brighton victory.
United could stick with the same side that beat Brighton, with Bryan Mbeumo and Amad Diallo linking well together in a 4-2 victory.