It has nothing to do with the supposed Nibiru, it does not match the description in size or anything else, plus, this planet is only hypothesized to exist at this stage, it has not been observed.
It is jumping the gun to assume this planet actually exists, and an even greater leap to associate it in any way with Nibiru which is a complete bunch of BS anyway. One shouldn't expect anything more from Sitchin, the great woo.
No planet Nibiru exists, and if any new planets are found which even remotely resemble it it will be down to pure chance alone, because Sitchin's and others reasons for assuming its existence were silly at best.
"All of our behavior can be traced to biological events about which we have no conscious knowledge: this has always suggested that free will is an illusion."
- Sam Harris