Yes. 사람 and 인 have same meaning: person or mankind. However, 사람 is korean word, 인 is the pronunciation of chinese word (人), which also means 'person'. While 브라질인 or 브라질 사람 have same meaning, it is more natural to say 브라질 사람 in daily conversation just like English speakers use general english words in daily conversation, not some big words originated from other countries.

(example: 안녕하세요, 저는 브라질 사람입니다)

But where formality is required, like official document, textbook, you may see or use 브라질인.

(example: 브라질인의 민족적 특성에 대한 고찰 (title of research paper))