We in India equate nationality with citizenship. In other words citizenship is synonimous with nationality. One cannot say one is Christian, Muslim or Hindu by nationality and an Indian citizen.
But when it comes to Indians living abroad as citizens of UK, USA, Malaysia and Sri Lanka, we like to think that they are Indian nationals.
Whenever some citizen of USA, who happened to be a citizen of India once, gets an award or goes in a spaceship, we celebrate. Mr. Shashi Tharoor in Sunday Times once wrote that we could even include Mr. Churchill in our list of Nobel winners of India because he spent a few years as an army Lieutenant.
In political science a nation is different from a state. Nation does not need geographical boundaries and soverienty. It is just the population and the we-feeling that makes a nation. Infact we have so many nationalities in India. Each caste is a nation. The bond among Khammas, Reddys, Velamas transcends Indianess.That is OK! But for example if a Roman Catholic were to say he was Vatican by nationality and Indian by citizenship, there would be furore.
By the way does Vikram Pandit hold an Indian passport? NRI should be one who holds an Indian passport but stays and works abroad.