Arsenals form is better than forests but that doesn't mean that their form is sound, compared to the previous season I think that they are a little slow now. This game is a tough one and your verdict isn't far from what I had in mind. Nottingham wouldn't want to give up easily so it would be a defensive game on their part which can lead to a draw but the chances of arsenal winning this game is quite high to me
For me at the moment there are only a few opponents who are equal to Arsenal like Liverpool, Chelsea and Manchester City while other teams not so playing against Nottingham is not a problem for Arsenal especially they are playing at home, we also have to remember that Arsenal were previously beaten by Liverpool so they have to win this match to stay on track. What we are looking forward to from Arsenal is the next match against Manchester City on September 21 I hope they don't lose any more points.
Manchester City is a shadow of itself now ,they have become weak unlike before when they were the most feared team in the premier League. looking at the H2H, Arsenal defeated Manchester City 5:1 at Emirates stadium last season and at that time, Manchester City were in a better Form than this season. For them to have loss to Brighton and Tottenham, I think Manchester City wouldn't be a problem for Arsenal. They will be defeated easily by Arsenal due to their poor recent performance. However I think the only teams that are close to equal Arsenal this season are Chelsea and Liverpool.