Northern Ireland vs capital of Northern Ireland

Northern Ireland and capital of Northern Ireland both are nouns.

Word	Noun	Adjective	Verb	Adverb
Northern Ireland	Yes	No	No	No
capital of Northern Ireland	Yes	No	No	No

Northern Ireland (noun)	capital of Northern Ireland (noun)
a division of the United Kingdom located on the northern part of the island of Ireland	capital and largest city of Northern Ireland; the center of Protestantism in Northern Ireland