Nilsson won four medals at the 2018 Olympic Games in Pyeongchang. On 13 February she became an Olympic champion, having won the gold medal in the individual sprint. On 17 and 21 February respectively, she won silver medals in the 4 × 5 km relay (with Anna Haag, Charlotte Kalla, and Ebba Andersson) and in the team sprint (with Charlotte Kalla). On 25 February Nilsson won the bronze medal in the 30 km classical mass start. She also finished 10th in the 15 km skiathlon. She finished second in the 2017–2018 Sprint World Cup, having won three individual sprint events over the season.