While direct download links aren't provided, here are the safe and proven ways to complete your in Spanish.
Insert the SD card into your Switch and boot into the Homebrew Launcher. retroarch roms pack espa%C3%B1ol nintendo switch
The most reliable source is the official libretro website. Go to buildbot.libretro.com and download the latest .7z file (the one with no date on the filename). While direct download links aren't provided, here are