I am not really a fan of the "Christian nationalism" label.
The "nationalism" bit carries too much baggage. But if I did want to identify myself as a Christian nationalist, Francis Scott Key's hymn "Before the Lord We Bow" would define the term for me. Key is best known to Americans as the author of our national anthem. But he also wrote several hymns. “Before the Lord We Bow," is his best, combining his love for nation, his eschatological outlook, and his political theology. Key would definitely be considered a "Christian nationalist" by many today. Here are the lyrics:
1 Before the Lord we bow,
The God who reigns above,
And rules the world below,
Boundless in power and love;
Our thanks we bring
In joy and praise,
Our hearts we raise
To heaven's high King.
2 The nation Thou hast blest
May well Thy love declare,
From foes and fears at rest,
Protected by Thy care.
For this fair land,
For this bright day,
Our thanks we pay--
Gifts of Thy hand.
3 May every mountain height,
Each vale and forest green,
Shine in Thy word's pure light,
And its rich fruits be seen!
May every tongue
Be tuned to praise,
And join to raise
A grateful song.
4 Earth! hear thy maker's voice,
The great Redeemer own,
Believe, obey, rejoice,
And worship Him alone;
Cast down thy pride,
Thy sin deplore,
And bow before
The Crucified.
5 And when in power He comes,
O may our native land,
From all its rending tombs,
Send forth a glorious band;
A countless throng
Ever to sing
To heaven's high King
Salvation's song.