Elizabeth's state of birth is mentioned in the death certificate of her son, Charles Milner Nichols. See "Iowa, Death Records, 1904-1951," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:Q248-4DK9 : 8 November 2017), Charles Milner Nichols, 29 Jan 1924, Liberty Township, Marshall, Iowa, United States; citing certificate #70320, State Historical Society of Iowa, Des Moines; FamilySearch digital folder 101784579.
Elizabeth's age (and, derived from that, her estimated year of birth), and state of birth, are available in the "United States Census, 1860", database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M82G-X74 : 19 March 2020), Charles M Nichols in entry for Ira Nichols, 1860.