Yup, it's burned out. If your lucky it's only the port that got burned out and not the system itself.
The Switch's USB-C port is specially rated and not every charger will work. Specifically you need one with a 56k Ohm Pull-up Resistor built in or it's going to happen again.
Check
https://www.reddit.com/r/NintendoSwitch/comments/6jnkl4/list_of_recommended_switch_usbc_chargers/ for a list of options or get an official charger. At the very least make sure you get one approved by Nintendo. It means it's been tested to work.