(With version 1.4 already reaching RC1, I haven’t used time to refine this post.)
Here’s what made 1.3.2 update/upgrade successfully for me. It took some time I’ll never get back! So I made this post to save other the trouble until 1.4 comes out (and with a headline that’s easy to find).
This is a mix of errata and this post from @bsd276.
% sudo pkg lock -y e2fsprogs
% sudo pkg lock -y consolekit2-1.2.1_1
% sudo pkg upgrade -y
% sudo pkg delete -y qt5-style-plugins
% sudo pkg install -y qt5-style-plugins
% sudo cp /usr/local/etc/dsbmd.conf.sample /usr/local/etc/dsbmd.conf
[reboot]
I could even update FreeBSD to 12.1-RELEASE-p12 with:
% sudo freebsd-update fetch install
I didn’t feel venturous enough to update to 12.2 as there could be some problems with deprecated python 2.7 and it’s libraries…
For everyone wondering. I left out a command, as in my case everything worked without it:
pkg delete -f librsvg2
and the /usr/local/etc/dsbmd.conf is a copy of the sample-file, so no need to back it up.
Have a successfull upgrade of your NomadBSD 
NB.
Remember that the local package-cache resides on a RAM-disk, so if it takes you a considerable amount of time to download the packages AND you have problems upgrading. It might be a good idea to backup /tmp/pkg before reboot and restore afterwards
or
Install NomadBSD on disk before upgrading.
, now I feel bad for just copying the errata 