national capital vs capital of Botswana

national capital and capital of Botswana both are nouns.

Word	Noun	Adjective	Verb	Adverb
national capital	Yes	No	No	No
capital of Botswana	Yes	No	No	No

national capital (noun)	capital of Botswana (noun)
the capital city of a nation	capital and largest city of Botswana in the extreme southeast