Nationalism is inherently Exclusionary. It directly goes against the word of Christ.
Galatians 3:28 - "There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus."
The Christian nationalist movement is anti Christian. It erodes the separation of Church and state, freedom of religion, and it corrupts the gospel by giving it a worldly lens and the state becomes an idol instead of God.