All versions of Nobara come with the Nobara Package Manager pre-installed.
The Nobara Package Manager allows installation and management of both system packages and flatpak applications.
The KDE version of Nobara additionally comes with plasma-discover
which can alternatively be used to manage flatpaks. It is not able to manage system packages.
The GNOME version of Nobara additionally comes with gnome-software
which can alternatively be used to manage flatpaks. It is not able to manage system packages.