is there an easy way to change the pathname for the clips in a project?
Not one after the other, but all at once?
You can select in the Nucoda bins all clips and open the properties, but the path is changed only for a clip.
Is there a better way?
There is a sneaky way ;-)
Select the compositipn you want to update in the library - save as a content files (use the Save button in the Library - there is also a load button to load it again)
This will save the whole composition - including the material and grades as a text file - the file paths are also in there.
You should be able to search and replace the file paths, then just reload the content file and it should be ok - you will lose renders.