Nephi’s vision now turns to the events surrounding the mortal Messiah and the New World. The verbal tense is s little difficult at the beginning, as it might appear that Jesus was born first, and then came the signs of his birth. This is simply an awkward construction, not an error. The signs of the birth are conflated with the signs of his death. While Nephi may understand the particulars of the miraculous events tied to each event (the birth ad death) he makes no real distinction between them here.
Nephi’s concern is the contrast between the signs of the Savior and the deeds of those who would persecute believers in the Savior. In Nephi’s prophetic understanding, the destructions that will accompany the death of the Savior are directly related to the wickedness of those who persecute the believers at the birth of the Savior. While Nephi understands that this is not the cleansing apocalypse of the last days, it nevertheless highlights Nephi’s understanding of history, where the destructions of Israel were related to sin, and the future destruction at the time of the death of Christ will also be related to a cleansing of wickedness.
Nephi is seeing history in typological sense, not a historical one. Just as Isaiah can indicate that Assyria is but a tool of the wrath of God, so does Nephi see the destructions accompanying the death of Christ in a symbolic sense rather than a physical one. Whatever the physical causes of the destructions (with the specifics pointing to multiple volcanic actions) it is not the natural cause the but the divine cause of retribution that informs Nephi’s interpretation of those events.