Credit to @lemnos and all contributors.
Currently, the theme change has to be a bit manual. To have access to the list of all the themes,
ls ./themes/themes
To use the dracula
theme for instance, please run
use ./themes/themes/dracula.nu
$env.config = ($env.config | merge {color_config: (dracula)})
The theme should be activated!
Here are screenshots of our themes.