i dont think there is any truth to this nibiru thing and even if there is there wont be any mass damage as it is said all over the forums and even if there is a mass damage you would need God's help to survive that. so just chill
above that the counter argument always put by the debunkers is that if there was such a object and was going to collide or cause any sort of damage to earth in the near future (as near as 2012) then there are so many independent astronomers who would have spotted it which i think is logical. well you can control NASA and other secrets but you cant control each and every astronomer who has got telescopes at their homes and for whom astronomy is a hobby.
i think if anything bad is going to happen in the near future will only be because of man-made disasters like WAR.