In February 2019, Nielsen returned to the NWSL signing with the Washington Spirit.

In November 2018, Nielsen signed with Canberra United in the W-League. She departed the club in December after making five appearances for the team.

In January 2016, Nielsen was selected as the 25th overall pick of the 2016 NWSL College Draft by the Seattle Reign, becoming the first Nebraskan native to be drafted by an NWSL team. She signed with the club in May of the same year. She made her debut for the club in a match against the Chicago Red Stars on May 22. The following week, she played the full ninety minutes in the forward position in a friendly against recent FA WSL champion Arsenal L.F.C.. Nielsen was waived by the Reign in July 2016.

After short stint with Apollon in Cyprus, Nielsen signed with the Western Sydney Wanderers for the 2016-17 W-League season where she started all twelve games for the Wanderers.

Nielsen attended the University of North Carolina, Chapel Hill from 2012 to 2015 where she played for the Tar Heels. During her freshman season, Nielsen played in 20 games for the Tar Heels, starting five. That same year, the team won the NCAA Division I Women’s Soccer Championship for the 21st time. The following year, Nielsen ranked fourth on the team in goals scored. She finished her sophomore season with six goals and four assists. During her junior season in 2014, she played in 20 games, starting nine. Four of the five goals she scored were game-winning goals, which ranked first on the team in game-winning goals. Nielsen captained the Tar Heels during her senior season and finished her collegiate career with 13 goals and 7 assists playing as both a defender and forward.

Born in Lincoln, Nebraska to Kathy Nielsen, Paige attended Lincoln Southeast High School where she was a four-year varsity soccer player. She was twice named a Nebraska Gatorade Player of the Year nominee in 2011 and 2012. She set new school records after ending her high school career with 79 goals and 35 assists. She was twice-named to All-State, All-Conference and All-City soccer teams.

Nielsen played club soccer for Toro Bravo soccer in Omaha, Nebraska and helped lead the team to three state championships, the Midwest Regional League championship in 2011, and National League Red Division championship in 2012. She played for the Nebraska Olympic Development (ODP) team from 2007 to 2010.

Paige Kathleen Nielsen (born October 14, 1993) is an American soccer defender who currently plays for Washington Spirit in the National Women’s Soccer League.