Mormon gives us three categories of people based on their response to this prophetic incident. There are some who believe. There are some who do not believe. There are some who think Nephi is a god. Does not this last category indicate that they also believe?
The answer is yes and no, and is the reason that Mormon creates this third category. There are people who believe, and understand the gospel. It is these people who are listed as the believers. To them, Nephi is a prophet, and the leader of the true church.
Those who believe Nephi to be a god might believe in Nephi as something unworldly, but they do not understand the gospel. They are those who are indoctrinated into the worldview of the outside world, where there are many gods. The Lamanites of King Lamoni were similarly impressed with Ammon, and similarly thought that Ammon might be a god – specifically the “great spirit.” (see Alma 18:3). Mormon is telling us that the social construction of the Nephite world at this point in time includes some who follow the Lamanite traditions, and are accepting of many gods, even gods among men. They do not, however, accept the gospel.
Textual: There is no chapter break at this point in the 1830 edition.