My guess is that Nordic walking uses shorter poles than the usual
classic skiing pole to achieve an elbow angle between 90 and 120
degrees. A normal walking stance (at least my normal walking stance)
is closer to an upright body position in contrast to a normal classic
(track) skiing stance with a forward body lean. I find that a walking
pole feels more natural when set to alpine length with forearm
horizontal at pole plant. I find myself using a shorter arm swing
walking that skiing because I do not have "pole glide" while walking.

That said, you would be using a pole length similar to your classic
pole if you are doing ski bounding simulating your classic stride.
While classic ski bounding you are using a more agressive arm swing and
forward body position than Nordic walking and you would also be using
more follow through pole push while bounding.

Edgar