Niua began his rugby career with the East Palo Alto Razorbacks, winning a Division II National Championship in 2009. He also won a Rugby Super League title with San Francisco Golden Gate. Niua made his international debut with the Men’s Eagles Sevens at the 2011 Pan American Games, where he started at flyhalf and led the team in scoring with 41 points on the way to a bronze medal. In 15s, he earned his first cap against Canada August 17, 2013. In February of 2014, Niua signed with the Glasgow Warriors of the Guinness PRO12 in Scotland, but was released following the end of the season.
Niua led the U.S. in Series appearances during the 2015-16 season and was fifth on the team in scoring with 55 points. Also fifth all-time in points, he will look to upgrade his Pan Am Games 2011 bronze medal as part of Team USA's Rio 2016 Olympic Summer Games Rugby Sevens squad.