Speaking ahead of tonight's NPD release, Nelson said: "I found out we ran out of consoles at end of the month so don't expect to win Dec."
He added: "Jan/Feb supply is tight as well. Likely amazing YOY growth numbers for Xbox."
Analysts are predicting large sales for 360 over PS3, with both EEDAR and Michael Pachter pointing to the Microsoft console coming close to Wii sales for December.
Kinect launched last November globally, and was pushed hard on a marketing level in the US. Microsoft said at CES earlier this month that the motion sensor had shipped 8 million units within 60 days of launching.
We'll bring you the NPD data as soon as it's released this evening.