NASA

NASA hosts on their web site for and by kids, a NASA Kid Story [Aug 2002] which includes Nibiru as a planet in the solar system:

The 10 planets of our solar system, including Nibiru (planet of the passing) by Cpt. Rob

N ibiru, the planet in all the places of order, up to 5th, it might be the biggest current danger to earth cause of it's magnetic powers, which might cause devistation in June 2003, however this is just a theory. It has an elliptical orbit.

NASA Article [May 5, 2003]

Niburu and Other Nonsense
The wild stories about an approaching planet or comet are false! ... also there have been no unusual levels of earthquakes ... try Google searches on ‘Niburu’ or ‘Nancy Leider’. If you want the real story on Nibiru or Planet X, check out the following website http://www.badastronomy.com/bad/misc/planetx/index.html.

NASA of course does not report an inbound Planet X and denies that Planet X was discovered by the IRAS Team in 1983, as reported by the Washington Post at that time.