Back in the old Aperture days I used versioning quite often to help me decide between different developing pathways. I still use this in Capture One (particularly when I produce a black and white and a colour edit based on the same image.
I don’t think that there is a way to do this natively in Nitro. I could duplicate the image in Photos and that certainly works, but it would be nice to do this in a way that didn’t produce a whole new image, but kept it within the development metadata.
Andrew