Most modern N-SL controllers can be updated directly through the console settings, similar to official Joy-Cons or Pro Controllers.
While third-party support varies, you should first try the standard Nintendo Switch update process to see if the console recognizes the controller's internal software: Navigate to from the Home Menu. Scroll down to Controllers and Sensors . Select Update Controllers . n-sl wireless controller firmware update
Solving specific issues like the "drifting" of sticks or sudden disconnections. Method 1: Updating via Nintendo Switch Console Most modern N-SL controllers can be updated directly