The USA has NEVER been a white or a Christian nation. The Southwest was settled by Hispanics, and the east was built bu white and black slave labour. You have three founding ethnicities. The Founding Fathers were all white men, because the Southwest wasn't part of the US at that time, and blacks had no freedom or power at the time.
The USA was settled by people fleeing religious persecution in Europe. The USA was founded as a religious sanctuary. No state religion and separation of Church and state.
No, you are not a "white Christian nationalist country" and you never were.