Nottingham in my opinion are the most improved this season, no one thought they would still be performing well till now they have shown their ability this season and it safe to say that they have a spot already in the top 4 because they don’t look like a team that will relent or drop performance now. I don’t think Manchester United can cause any harm to them as it stands but we can’t be so sure yet as anything can happen in football. This will be a tough meeting for Amorim and his team, their hopes of getting a better position before the end of the season might be postponed because Nottingham will not be an easy opponent.
Exactly, Nottm Forest has shown a very significant performance improvement this season, since the beginning of the season. If we look at it from the defensive and offensive side, it is indeed very far from last season.

Check the following statistics:
1. Their ranking rose from 17th to 3rd, even beating Man City and several other top clubs.
2. Their current number of points is almost 2x the total number of points last season, which was 32 last season and now they have collected 54 points.
3, Nottm Forest has only lost 7 times this season, while last season, they could only win 9 times, and lost 20 times.

This is the most successful performance improvement in the EPL this season.