Are you using a screen protector?
Try removing the screen protector and see if this fixes the problem.
Reattach the screen protector, making sure that no dirt or air is trapped between the screen protector and the screen. Use the Nintendo Switch screen protector (HAC-018) (sold separately) if you are not doing so already.
Check to make sure that the touch screen is working properly.
Start System Settings from the HOME Menu, then select Controllers and Sensors ⇒ Test Input Devices ⇒ Test Touch Screen.
If the touch screen is still not working properly, please contact Nintendo Consumer Support.