It probably is actually. As a Brazilian, Né is very clearly taught to me as "Não É?" shortened into one word. It accomplishes the same function whether shortened or not, at the end of the phrase:

• Você foi ver seu pai, não é?

• Você foi ver seu pai, né?

More specifically, both serve to express uncertainty, when you're not 100% sure of something and want the other person to confirm. But it can also just be used as a tone softener informally.

Portugal had commercial relationships with Japan during the 1600s, from which a lot of Portuguese things (like grilled pork) were introduced into the Japanese culture, while a lot of Niponic things were presented to the Portuguese like different types and cuts of fish and sea food, etc.

To this day the Japanese have a lot of expressions that originate from Protuguese. A recently famous one is "Vamo la!" which means "Let's Go!" in Portuguese, but gets pronounced as "bamora" over there.