Hi,
SolidWorks has an option of finding a part in a very large assembly by clicking on his location in the tree.
Once you click on it, the view will navigate right to the part.
Does NX have something similar?................
Also, there is a command called "fit view to selection" that may help. It works on any selected geometry. It probably won't appear in the standard ribbon tabs, so use the command finder and/or "customize" to put it in a convenient location.
The part navigator has an option to scroll to the feature that has been selected in the graphics window. I'm not sure if this option will automatically expand feature groups or not.