Please try the below:
1. We recommend using the official Nothing charger and cable.
2. Replace the charger and cable to check if the adapter or cable is defective.
3. Avoid using high-power apps when charging, especially games, videos, camera, etc. If your phone is seriously overheated, restart it and wait for the temperature to drop before charging again.
4. If the ambient temperature is too high or too low, it will affect the phone's charging speed. Charge the phone in a suitable environment of 15℃~35℃.
5. Restart your phone and re-plug and unplug the cable to try charging.
If the issue persists, contact our Customer Support for further assistance.