Nibiru is a nick name for brown/red dwarf planet that more than likely exists due to huge evidence of major cataclysmic events on planet earth in the last 4 billion years. Our planet was thrown of it axis many times in the last 4 billions years, also earth's poles flipped at least few times during that period. This can only be cause by immense gravitational pull from much larger object coming to close to earth. One cannot reject such an evidence. It happened many times before and it will happen again. When? No one knows.
In my opinion, it can't come soon enough for me. Bring it on!!