If you are using a blacklist file in /etc/modprobe.d and it’s not workign, what worked for me was changing my kernel command line to this in /etc/default/grub
… then doing a
sudo update-grub and rebooting.
lsmod | grep nouveau
Nvidia might want to update it’s installer, since in the latest 18.04.4 release /etc/modprobe.d seems to be ignored, at least when it comes to nouveau.