...The Book of Mormon clearly states that Nephi built a temple modeled upon the temple of Solomon upon arriving in the Americas (2 Nephi 5:16). In addition, the Book of Mormon says that other temples were built in the Americas (see 3 Nephi 11:1 and Helaman 3:14)...the Israelites in the Americas were trying to faithfully follow the law of Moses...From a commentary:
Ne 5:16 I, Nephi, did build a templeAnd more.
This temple was fashioned, as Nephi says, after the temple of Solomon. It is fair to conclude that they practiced the same forms of animal sacrifice that were performed in the temple in Jerusalem. The only difference between the administration of the temple of Solomon and Nephi’s temple is that the Nephites were not of the tribe of Levi, and therefore the priesthood they held was the Melchizedek priesthood (2 Ne 6:2). As Melchizedek priesthood holders, they could administer all the temple ordinances which were done according to the Levitical order.