If the two D-man have very similar stats.. then I would keep Parayko and drop Nurse. For the simple reasoning of diversification among teams.
Also... I would be curious to take a deeper look at Nurse's stats when Klefbom was out. I heard that Nurse wasn't the top D on the PP with Klefbom injured and that Ethan Bear was... so if thats the case I think Nurse will get passed by Bear and eventually Bouchard on the point producing roles.