Nephi sees the destruction that will precede the descent of the resurrected Jesus from the sky. Even in vision, this must have been an impressive destruction. Nephi appears to experience it, not simply see it. He says that he sees lightnings, but also that he hears thunderings and all manner of tumultuous noises. It is impressive to modern readers when we do no more than read it. It must have been supernally emotional to experience it as Nephi did.
The glorious result of the terrible destruction is that the resurrected Christ descends from heaven. Simply the appearance of Nephi’s God to his descendants would have been impressive, but the contrast was even more dramatic.
Mormon later writes the fulfillment of this prophetic vision, but he will give no indication that this prophecy had been so detailed. Mormon also indicates that he had not known of the small plates until he found them while searching for more information on king Benjamin’s reign. This suggests that the small plates had faded from Nephite memory, and that this marvelous vision wasn’t commonly available in order to predict the events that ultimately fulfilled the prophecy.