Nephi was a great king and protector, much like king Benjamin, For behold, king Benjamin was a holy man, and he did reign over his people in righteousness… Wherefore, king Benjamin, by laboring with all the might of his body and the faculty of his whole soul, and also the prophets, did once more establish peace in the land (W of M 1:17-18).
Jacob explains that Nephi wielded the sword of Laban in their defence. Nevertheless, we are not going to hear any details about their wars on the small plates of Nephi. All we learn from Nephi is that he made many swords after the manner of the sword of Laban and that by 559 BC, they had already had wars and contentions with [their] brethren (2 Nephi 5:14, 34).