Historians (Nepali, Indian or otherwise) claim that he was born in Lumbini. They may be right, they may be wrong. Perhaps we should check the Nepal/India boundary in the year 563 BC. We all know that boundaries have changed due to forces of war & politics. As far as I'm concerned what is significantly important is where He attained nirvana i.e. Bodhgaya because that's when He became enlightened and know as the Buddha. Prior to that he was very much a royal prince.

Buddha belongs to the world. Not to Nepal or India. Prince Siddharta has royal status. Buddha doesn't have a citizenship status. So, why are we being so petty over this insignificant matter? Does it make any difference? Will you become a better Buddhist just because he was born in Nepal? Instead of practising his teachings, all of you keep squabbling like spoilt children over a chocolate bar.

If you are so sure that Buddha is a Nepali, than PRACTICE WHAT HE PREACHED.