All links are taken from the Fortnite Nintendo Switch build archive which can be found here
You will need additional mods and patches in order to connect to a backend and play matches using these builds. You can find all the required patches, as well as a 24/7 hosted backend in our community's Discord server.
Fortnite was released for the Nintendo Switch on June 12th, 2018 during Chapter 1 Season 4. With that in mind, there are no earlier builds for the console prior to Season 4 (4.4.0) that have been released to the public.
Hosting the builds: SimplyBlk Orginal hosting of the builds ItsTendo (lintu)