Nasilasila grew up in Namatakula, the famous town known for creating rugby union and league stars like Noa Nadruku who is his uncle, Lote Tuqiri who is his cousin and Nemani Nadolo. He played rugby league and was part of the Fiji Residents Rugby league side, a feeder for the Fiji Bati. He wanted a career in rugby league and waited for 3 years for offers but then switched to rugby union joining a top local 7's club, Ratu Filise. He was spotted by then coach Ben Ryan who saw him playing in one of the local tournaments and included him in his extended side for the 2014 Gold Coast Sevens but an injury ruled him out on the eleventh hour. He made his debut at the 2014 Dubai Sevens making his debut against France scoring a try in their 54-7 thrashing. He did not make the Fiji side to the 2016 Olympic Games
