@jel.cos
Indeed, depth frame resolution is resized to 640x480 for further processing by Nuitrack. You don’t have to change anything in nuitrack.config because Nuitrack processes the depth frame in this resolution (640x480).
@vpenades
Nuitrack uses the OpenNI2 driver for OpenNI-compatible cameras (including Kinect), which causes noise as shown in your screenshot.