So I've recently got a new work computer, an epic Dell XPS 15, with Ubuntu installed, and I set out to install Valet for Linux and faced an issue installing.
[DomainException] Apt was unable to install [nginx].
After some furious googling, I found the answer, and suspect it'll be something other Linux users will face when setting up a new computer.
The culprit is the default Apache install of the OS, so we need to set about removing the hinderence.
sudo systemctl stop apache2.service
prevent apache2 to start at boot
sudo systemctl disable apache2.service
sudo apt-get install nginx