Nothing wrong with being white or any other race. I'm white. My family is white. Most of my coworkers are white. I have white friends! Nobody loves white folks more than Slobama, believe me!
Nothing wrong with being Christian, as long as you're actually following Christ's teachings and not weaponizing religion in a cultish way to justify, say, polygamy or child abuse. Would the Mormon Church know anything about that?
"Nationalism" connotes a kind of aggressive and brain-dead form of patriotism. Blind obedience to leaders, punching down at minorities and Jews, stomping on the rights of foreigners and the LGBTQ community, those sorts of things. To the extent those things are happening, nationalism is Bad. Benign, non-toxic love of one's country is what I would define as "patriotism," and that is fine.
Can't say I identify with white Christian nationalism at all. It seems to be 21st-century fascism plain and simple. But if you like it, knock yourself out.