Because of the way Nottm Forest has performed so far in their match this season, many people will be happy to see them if they finally make it as the top team that qualifies for Champions League next season. They look unstoppable in achieving their aim if you ask me because they have won and draw against strong teams better than Manchester United. Manchester United can stand in between if they face them in few days to come. At least they are the host team, they have the advantage to win the match against Manchester United.
With the high team spirit of the team I don't see Nottingham Forest leaving the top 4 any time soon and some of the bigger teams are definitely afraid of competing with them because they know that things have changed for this particular team that every other team do win them like is nothing, even Manchester City can't stand them or should I say Liverpool or Arsenal? They are unstoppable like you said and if they finish 3rd or 4th and book a spot in the champions league it will be their greatest achievement of this very campaign and the Manchester United you are talking about Forest are more organize than the Red Devils so I feel is going to be an easy 3pt when both team clash horns.