Just to clarify the question, what I mean is that when you say that you're Chinese (in the English language), for example, you could mean it both ethnicity and nationality-wise. But in Japanese, it's "中国人". Because of the kanji 国, it sounds like it pertains to nationality and not ethnicity, but there are Chinese people outside of China, like those in Taiwan or Malaysia.
e.g. You can say "I'm a Chinese living in Malaysia/I'm Chinese-Malaysian" and you'd understand that the person is a native Chinese in Malaysia, but if you say "私はマレーシアに住んでいる中国人です” it sounds (to me) as if a Japanese person would interpret it as someone from China is living in Malaysia. Is there any other way to say this or any other term to use that refers to ethnicity?
I've been wondering about this for quite some time now because unlike homogenous societies where you can tell someone your nationality for them to understand what ethnicity you likely are, you can't for culturally diverse countries.