It had a new Halo, Fallout, and StarWars this year. I could see it doing better.
See my post here for my reasons why I feel VGC is overtracking the XBO. Furthermore, Halo was a sales disappointment (relative to past Halo titles, anyway) and was only a moderate system-seller and is unlikely to move an appreciable amount of hardware for November. Star Wars is a marketing & bundle exclusive for the PS4 and thus was unlikely to have a measurable effect on XBO sales. Fallout 4 was probably the only game that shifted an appreciable amount of units, but I somehow doubt it could be so big of a system-seller so as to make up for the fact that the forces that drove the XBO to 1.23M last November are not a factor this November. In fact, if Amazon was any indication XBO sales did not move appreciably the week Fallout 4 debuted, and there wasn't exactly a ton of Fallout 4 bundles preordered, either.
I stand by my claim that VGC is overtracking the XBO by a considerable amount. They overtracked it by 200k last November (and their pre-adjustment estimates are frequently quite a bit off from NPD numbers), so it's not improbable that they didn't do so again this year.