No, that is not nationalism. It is certainly not American nationalism, and he is the president in The United States of America, not a non-existent "nation of alleged post colonial racial minorities". What you are doing is stretching one word, "nationalism" to include coalition building of many nations and minorities. He could, perhaps be called some kind of Kenian nationalist if he lived in Kenia, but he is not a nationalist for America where he lives and governs.
Conservatives are two kinds: strict libertarian capitalists and those who recognize that in addition to private property there is a cultural national property, just as much in need of protection. That second kind, usually called cultural conservatives, are nationalist conservatives because they believe in the need to conserve the national institutions. You are right: it is not bad at all.
NAtionalism does not depend on ones orifice,elected or appointed.
It is a social movement based on culture.
Obama is a minority nationalist. He says so himself.
Why in old hell do you think we have thousands of Latin children streaming across our Southern Border? Are they coming just to buy bubble gum and go home? Or are you just a theorist who cannot understand the context? Se puedo, se puedo!
Nationalism creates a nation. A nation is being created within the United States. We are no longer a melting pot. And Obama the minority nationalist is doing it.