Not too concerned about these superficial similarities. They don't even look that similar and I struggle to think of why Disney would even want to rip off Nadia.
Nadia
Our hero, Jean, a nerdy yet sweet inventor who gets caught up in a quest to find Atlantis. Along the way he falls in love with a girl unlike anyone he's ever met before. Accessories: big round glasses, red bow tie, assorted charts and scientific equipment.
Atlantis
Our hero, Milo, a nerdy yet sweet scholar who gets caught up in a quest to find Atlantis. Along the way he falls in love with a girl unlike anyone he's ever met before. Accessories: big round glasses, red bow tie, assorted charts and scientific equipment.
Nadia
The heroine, Nadia, an exotic young woman who turns out to be a princess of the lost empire of Atlantis. To save her empire from invaders, she must unleash her hidden power. Accessories: blue crystal pendant, skimpy bikini 'n' sarong costume, gold armband and hoop earings.
Atlantis
The heroine, Kida, an exotic young woman who turns out to be a princess of the lost empire of Atlantis. To save her empire from invaders, she must unleash her hidden power. Accessories: blue crystal pendant, skimpy bikini 'n' sarong costume, gold armband and hoop earings.
Nadia
To save Atlantis,
the heroine activates her pendant
and merges with the power source!
Atlantis
To save Atlantis,
the heroine activates her pendant
and merges with the power source!
http://www.newgrounds.com/lit/atlantis.html
are them the same exact story? no, but you can totally see that is completely inspired by gainax anime.