Okay, so first off I am going to assume that by "how can i speed up my nintendo switch", you mean "how can i make my nintendo switch's internet faster".
Disclaimer: This process may not speed up your connection if you are not located in either the US or Europe
So let's begin:
We are going to be changing your Nintendo Switch's DNS settings
The reason for this is because by using google's DNS on your Switch, this ensures that your console's DNS resolves correctly. By default, your Switch system will use your ISP (internet service provider) DNS. By switching to google's, this can mean faster resolve speeds. Google DNS often resolves hostnames much faster than many DNS servers that ISPs use.
- Go to the Switch's main home screen.
- Select System Settings from the menu at the bottom.
- Scroll down to the Internet section.
- Select Internet Settings.
- Select your internet connection.
- Scroll down and select DNS Settings (this defaults to automatic).
- Change your DNS settings to manual
- Now select Primary DNS
- Set primary DNS to 188.8.131.52 and press + button or "OK"
- Now select Secondary DNS
- Set secondary DNS to 184.108.40.206 and press + button or "OK"
- Now make sure you hit the save button on the right to save these new settings
- Now press the back button until you see Test Connection underneath Internet Settings
- After running this test, you should see "Test Connection Successful" - woohoo! now play some games.
If you run into any issues with your Switch's wifi after updating your Switch's DNS settings, hold down the power button and then power off your console / restart the system. Then turn it back on and re-test your wifi. This should resolve any old DNS cache that might still be lingering on your console.