national capital vs capital of Tibet

national capital and capital of Tibet both are nouns.

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

national capital (noun)	capital of Tibet (noun)
the capital city of a nation	the sacred city of Lamaism; known as the Forbidden City for its former inaccessibility and hostility to strangers