Select NURBS object. > Modify panel > Create Curves rollout > Dependent Curves group box > Curve Fit button
Select NURBS object. > Modify panel > NURBS toolbox > Create Fit Curve button
This command creates a point curve fitted to points you select. The points can be part of previously created point curve and point surface objects, or they can be point sub-objects you created explicitly. They can't be CVs.