https://www.techradar.com/news/fortnite-battle-royale-on-switch-remains-free-to-play

Fortnite fans will be pleased to discover that playing the Battle Royale game online on Nintendo Switch consoles will not require a paid subscription to Nintendo’s Online service. The details of the service were revealed as part of Thursday’s Nintendo Direct announcement.

Access to the online features of many Switch games will cost a $3.99 / £3.49 / AU$5.95 monthly or $19.99 / £17.99 / AU$29.95 yearly fee.