Final answer:
The statement is false; Joseph Smith founded Nauvoo in Illinois, not Utah, and it became the largest utopian community for the Mormons before their move to Utah under Brigham Young's leadership.
Step-by-step explanation:
The statement 'Nauvoo was founded by Joseph Smith in Utah as the Mormons' religious capital' is false. Nauvoo was founded by Joseph Smith in Illinois as a new center for the members of the Church of Jesus Christ of Latter-day Saints, also known as Mormons. It became the largest utopian community in the United States in the 1840s. After Smith's death, Brigham Young led the Mormons on their trek to Utah, which later became the religious capital for the Mormons.