The nickname everyone enjoys still belongs first to the person carrying it.

A nickname is used by many people and lived in by one. The group gets the pleasure of it a few times a week; the person named carries it everywhere, including into rooms where it does not land the way it does at home. That difference in exposure is why their opinion of it outweighs everyone else’s. Enjoyment on one side is not the same as permission from the other.

Ask, once, plainly, whether they actually like it, and make it easy to say no. And if a name of yours has stopped fitting, you are allowed to retire it, even one people have used for twenty years.