Further reading into the process, I have learned something.
The rated hardness of the nitride process is as close to make little difference to chrome. Though depending on the specs for chrome thickness (I am ignorant of the spec offhand without looking it up) the chrome lining may be thicker.
So it may be the more uniform bore and therefore better accuracy that is the main draw of nitride. That is, if it is more accurate, though I would suspect it would be if the barrel was quality.