Following his military service, Nieves returned to Franklin County. He currently resides in Washington, Missouri with his wife, Julie, and their three children: Alexandra, Moriah, and Victor.
Nieves is the host of a morning talk radio show called "The Patriot Enclave" on KWMO 1350 AM in Washington, MO and functions as KWMO's marketing director. He and his wife also operate Nieves Enterprises and Hwy 66 Auto Sales. Additionally, Nieves serves as a high school substitute teacher and is also a zone pastor of Living Bread Church. Nieves frequently speaks to groups about small business operations, concentrating in the areas of professional development and team building.
In August 2010, Nieves was accused of assaulting an opponents' campaign worker, Shawn Bell, following a contentious primary election which Nieves won, during a visit by Bell to Nieves' campaign headquarters while he and his campaign manager were winding down the campaign. Nieves denied any assault had occurred and his campaign manager, who was present during the entire visit by Bell, concurred with this denial. On September 10, 2010, Franklin County Prosecuter Bob Parks announced he would not be seeking criminal charges against Nieves, commenting that he could not prove that a criminal act had occurred. Shawn Bell announced in a statement that he still planned to file a civil lawsuit against Nieves, while Nieves told the Washington Missourian that he was ready to forgive Bell.
A new 98th District was created after redistricting following the 2000 census. The 110th and 98th merged into the new (98th) District. In 2002, Nieves ran to replace outgoing State Representatives May Scheve(D) and Francis Overschmidt(D). Nieves won a primary race against Dave Bailey, and won a general election contest against Tom Herbst. He won reelection in 2004, 2006, and 2008. His term expired in 2010, at which point he ran to succeed John Griesheimer as a state senator.