Alma 50:23

But behold, there never was a happier time among the people of Nephi, since the days of Nephi, than in the days of Moroni; yea, even at this time, in the twenty and first year of the reign of the Judges.

There had never been a happier time for the Nephites since the days of Nephi than in the days of Moroni. This was true in the twenty-first year of the judges.

But there had never been a happier time among the Nephites since Nephi’s day than during Moroni’s time—right then, in the twenty-first year of the judges.