At the 2018 European Athletics U18 Championships, Nacheva won silver in triple jump with 13.88m, behind Spaniard María Vicente with 13.95m. On 15 July 2018 she won gold in triple jump at the 2018 IAAF World U20 Championships, becoming the first Bulgarian athlete to win in the age group since Tezdzhan Naimova in Beijing 2006. Her result of 14.18m was a personal best and the world leading for the year so far. She became the second Bulgarian female triple jumper to win the Junior world title, after Tereza Marinova, whose 14.62m result in Atlanta 1996 remains the world record.