I downloaded nrfconnect-3.3.0-x86_64.AppImage from https://www.nordicsemi.com/Software-and-tools/Development-Tools/nRF-Connect-for-desktop/Download#infotabs.
I cannot start the application by calling:
chmod +x nrfconnect-3.3.0-x86_64.AppImage sudo ./nrfconnect-3.3.0-x86_64.AppImage