Alma 62:48

And the people of Nephi began to prosper again in the land, and began to multiply and to wax exceeding strong again in the land. And they began to grow exceeding rich;

The people of Nephi began to do well again in the land. They began to grow in number and become very strong again in the land. They began to grow very rich.

The Nephites began to thrive again. They multiplied and grew very strong in the land. They became extremely prosperous.