"Right" is just a social construct that doesn't exist in reality. "Right" only works when someone can manifest it into action, with force or political power or external help or whatever. If you dump all these talks about human and nation rights, in the end only ability to achieve matters.
I.e. Kurds tried but failed because their allies wouldn't want to help them, and they by themselves couldn't create state because of many reasons. Catalans aren't successful too, because everyone around (EU) don't want this, and they could only protest, but not fight. Want independence? Just kick out Spanish government from your land (that may end in long civil war). If you can't allow war, your independence desire and all these "rights" are nothing. Kurds are trying though.
Being real "nation" (as some entity) or not doesn't matter much, especially because nation is a imaginary construct too. No one deserves anything by default. Although modern times aren't good for independence movements at all.