Although Manchester United is a strong team, their performances cannot be relied upon. .The performance of this group is very erratic. And so I refrained from betting on this match.
I'm sorry, I can't say Man United is a strong team anymore. Man United looks like an average team, they didn't play consistently during this season. Although sometimes they showed their power, but in the other occasion they showed their weakness. Since they become an unstable team, I only can say that Man United is an average team only. 
Manchester United probably won't win today's match. At the end of 85 minutes, they could not score any goal. The match is now in a goalless draw. But the performance of Nottingham Forest players is surprising me. I thought the team would probably play a defensive strategy. But Nottingham Forest players are doing a lot of attacking. They have taken a total of 16 shots so far, 5 of which were on target. On the other hand, Manchester United players made 19 shots. Of these, 6 were on target.
They are leading with 1 goal. Casemiro scored a single goal in minute 89'. The match against Nottm Forest looked very tight, Man United is like against a big team in EPL. 
However, Man United deserves to win the match, they could play better in this match. But I'm not sure Man United may reach the final round if they only can play like this match. They make 20 shots but only could score 1 goal. Man United attackers have lack accuracy in shooting.