If you are very skilled in using the Navigate function found under View- Operation, you can capture a video of the fly-through.
( difficult...)
If you have the correct license level of the Vis - Viewer, it's easier to do the fly-through.
I don't think the fly mode exist in the lowest level license, - ?
Another option, also quite difficult to set up as desired , is the View- options- navigate Options... where you can define "keyframes" in between which NX will interpolate the movement, or use a "trajectory curve" along which the camera will move.
This fly-through can be rendered into a video or screen dumped into a video.
The keyframes / trajectory curve method can be step by step edited into the desired fly path.
Regards,
Tomas