Nephi now repeats his cycle of sin/salvation. When he begins the psalm he starts with his blessings and moves to his temptations. He then describes the goodness of God, and now is cycling back to his temptations. He will finish with a personal exhortation to return to harmony with God.
Perhaps Nephi is using this set of literary parallels to describe the natural tendency of humanity to wrestle continually with temptation, even after periods of great righteousness. With the structure of the psalm, Nephi mirrors experience.