Most of the details on this song cluster has been gone over in other threads.
There is no mention of a "nation" or similar in any of the British Isles antecedents.
The first American version, with the general theme of "Streets of Laredo," was "Tom Sherman's Barroom." No mention of a "nation" there. Stewie posted a very late version of this song, which was apparently written by F. H. Maynard, about 1876, based on a song popular with cowboys, called "The Dying Girl's Lament." See Guy Logsdon, 1989, "The Whorehouse Bells Were Ringing," p. 289ff., Univ. Illinois Press.
No early version of the song has been posted here. The first verse (Austin E. and Alta S. Fife) is:

As I passed by Tom Sherman's barroom,
Tom Sherman's Barroom quite early one morn,
I spied a young cowboy all dressed in his buckskins,
All dressed in his buckskins and fit for the grave.

No mention of a "nation." There is a comprehensive analysis, including references to field recordings and manuscripts, and bibliography, in the Fife's notes to "Songs of the Cowboys," N. Howard (Jack) Thorp, 1966, pp. 148-190.
In a small booklet published at Estancia, NM, in 1908, N. Howard Thorp published his version. No mention of a "nation." The booklet is reproduced in the book referenced above ("Songs of the Cowboys," News, Print Shop). His version has not yet been posted here.
Another 1908 version (Sharlott Hall) appeared in Arizona (no "Nation").

The verse quoted by Robin, with "Nation," at the top of this thread first appeared in John A. Lomax, 1910, Cowboy Songs, p. 74-76. (The "He" in the third line appears there. The "He" is repeated in the enlarged 1938 ed.). The "nation" first appears in this text.
Just where Lomax got this text is uncertain. Many years later, he claimed to have obtained the song in Texas. In 1960 he went back to a brief late version of Tom Sherman's Barroom and used the title "The Dying Cowboy," "Folksongs of North America," 1960. No mention of the "Nation." Along with it, he published an English version of "The Sailor Cut Down in His Prime" (pp. 184-186).
Noted in a previous thread (3918) is use of the song by Owen Wister in his novel, "Lin McLean," 1898. No mention of a nation, but the song is incomplete.

"Friends" and "relations" are mentioned in the version printed in 1908 by Thorp.

"Farewell my friends, farewell my relations
My earthly career has cost me sore"
The cow-boy ceased talking, they knew he was dying
His trials on earth, forever were o'er.

Much information in thread 3918: white linen

Tom Sherman, thread 20413: Tom Sherman

Several threads on British Isles antecedents.