Literary: Nephi follows Isaiah 11:5 precisely.
2 Nephi 30:12
12 And then shall the wolf dwell with the lamb; and the leopard shall lie down with the kid, and the calf, and the young lion, and the fatling, together; and a little child shall lead them.
Literary: Nephi makes only a slight change in Isaiah 11:6:
6 The wolf also shall dwell with the lamb, and the leopard shall lie down with the kid; and the calf and the young lion and the fatling together; and a little child shall lead them.
The change comes not in the text, but in the introduction to the text. Nephi adds “and then” (with the shift in timing requiring a minor shift in the word order as well). This addition should not be seen as a variant, but as the result of an integration of Isaiah into Nephi’s text. Nephi is not using Isaiah as fixed sacred text, but rather as a dynamic and integrated part of his message. Thus Isaiah the historical text comes alive in Nephi and is amenable to the same tenses and meanings as the rest of Nephi’s discourse. This is a change that comes from the way Nephi is using the text, not from any putative translation of Isaiah.