Even though nomenclature includes naming, but not vice versa, I prefer naming. The purpose of the tags is to aid the user, and naming will be more helpful than a word someone has to look up. I agree that combining the two is a good idea.
From Merriam-Webster, nomenclature:
1 : name, designation
2 : the act or process or an instance of naming
3a: a system or set of terms or symbols especially in a particular science, discipline, or art
3b: an international system of standardized New Latin names used in biology for kinds and groups of kinds of animals and plants
Definition of naming, from Dictionary.com Examples are for named, but they can all be converted to naming, e.g., I am naming the baby Susan.
verb (used with object), named, naming.
to give a name to: to name a baby.
to accuse: He was named as the thief.
to call by an epithet: They named her speedy.
to identify, specify, or mention by name:Three persons were named in the report.
to designate for some duty or office; nominate or appoint: I have named you for the position.
to specify; suggest: Name a price.
to give the name of: Can you name the capital of Ohio