Ditto.
For four reasons -
Nolan is totted as a guy whose best coaching quality is that he can get guys to work - yet even Nolan appears to agree with the general consensus that the guys aren't working it. Meaning his best coaching tactic/attribute is... umm... well not working (aka: broken)
Secondly, each one of the so-called top six has performed better, and recently, together and/or on other teams, than they've performed for a good 15+% of the season now. Meaning other coaches have brought more out of these same guys.
Third, this isn't just one or two guys floundering. This is 6 proven 20+ goal scorers, 3 of whom are in their prime (Moulson, Stafford, Stewart) and 2 of whom are young enough they ought reasonably to be improving (Ennis, Hodgson). When the whole team flounders it's the common denominator (aka: coach) not putting them in best the position to bring their best.
Fourth, this is not just a slow start or a cool stretch any longer, this is a wholesale trend - a team full of the proven offensive production and nose to the work bottom six should at least have 1 awesome game on the season. These guys have not even that blip.