According to the docs, Kiwi can build Ubuntu images:
https://suse.github.io/kiwi/building.html?highlight=ubuntu
Is it possible to install Kiwi on Ubuntu and create the image from there or are there only packages for Suse?
Looks like only RPM packages are created
https://software.opensuse.org/package/kiwi
That said, someone possibly could try building deb packages from source using the OBS service (It’s the online version of Kiwi).
But,
I don’t know how much has changed, close to a decade ago i remember there was one project where I had to build an app from source to run on Ubuntu, and my recollection is that the whole process for both building and executing on Ubuntu was very, very different than on openSUSE. Since then, there have been many architectural changes but I’m sure some of those differences should still exist. At the very least, the selection of build components is still organized very differently than what we have in openSUSE, so I don’t know if Kiwi even makes sense building with those components.
Although you may enjoy the simplicity and ease of creating things in Kiwi, you may want to use whatever is recommended on Ubuntu.
TSU