"Now more than never" does not make sense in English, if you think it does then you have been mishearing that phrase. Nunca can translate as both never or ever, depending on the context. Obviously "eu nunca.." would translate as "I never.." but "... que nunca" would translate as "... than ever".
It's just a question of double negative I think, not "nunca" translating to "ever." It's a bit like "I have not heard anything" being "I have not heard nothing" in Portuguese (I won't try to write it here since it would be awful). Maybe that means that "nada" can mean "anything" but I think that's misleading. It's just that double negatives are negative in some languages and positive in others.