Isaiah 9:1 (King James Bible) when at the first he lightly afflicted the land of Zebulun
The 1837 edition deleted the definite article the from the archaic phrase “at the first”. The King James Version has many more examples of “at the first” (26 in all) than “at first” (only one, in John 10:40). The only other occurrence of “at (the) first” in the Book of Mormon is in Alma 32:26, which reads “at first” in both manuscripts and all editions. The omitted the in the 1837 edition for 1 Nephi 19:1 may be unintentional rather than the result of Joseph Smith’s editing since the change is not marked in the printer’s manuscript. Modern English, of course, has “at first”, not “at the first”. The critical text will restore the original usage, as did the 1908 RLDS edition.
Summary: Maintain in 2 Nephi 19:1 “at the first”, the original reading of the Book of Mormon text (which is the same here as the King James reading).