Manchester United have two difficult games in premier league when facing Nottingham Forest with consistent performance this season and Manchester City have higher standings position than United. I don't expected with Manchester United will secure three or one points for upcoming two consecutives match in premier league by facing Nottingham Forest and Manchester City, last victory by defeating the relegation standings team Leicester City can't guarantee for Manchester United will secure three points by defeating Nottingham Forest have winning trend in last several matches before.
Chelsea have almost the same problem with United in this season, not consistent keep in the winning race make top fourth position almost difficult if losses for several matches left. Have bit problem with Cole Palmer injury and he was absent for England national teams at world cup qualifier match in this week.
These are very tough games for Manchester United in the coming weeks. With the recent improvement and good results United have been getting I think they will fare well against these two teams, probably get a draw against Nottingham Forest and a win against Manchester City. For Chelsea I can’t point out what the actual problem is honestly, their drop in form is surprising.
Actually, there's not much difference between Chelsea and Manchester United. I also still find it difficult to know their main problem, although Chelsea were really doing well in the early stages of the season, but right now they have a decline in performance, which is still unknown to many fans, although Manchester United are still better but still unable to keep their winning streak, which is affecting them. Amorim needs to work harder to keep the team consistent.
Furthermore, Manchester United will be facing City and Nottingham Forest, as you said, and this is going to be a difficult one for them, seriously, because Manchester City are doing better than Manchester United currently.