A LAN adapter is not required for Nintendo Switch dock with LAN (Model No. HEG-007), because it includes a built-in LAN port. If using a Nintendo Switch dock without a built-in LAN port, a USB LAN adapter is required to establish a wired internet connection.
A USB LAN Adapter can be connected to Nintendo Switch Lite using a licensed accessory, such as the Dual USB PlayStand for Nintendo Switch Lite from HORI.
For Nintendo Switch, the following LAN Adapters are recommended:
Wii LAN Adapter (model number RVL 015).
Wired Internet LAN Adapter for Nintendo Switch by HORI.
The Nintendo Switch system is also compatible with Nintendo Switch dock with LAN (Model No. HEG-007) that is included with the Nintendo Switch – OLED Model system bundles. This dock can be purchased separately.