this should work:
vscode
new window
open folder: /etc/nixos
open file: configuration.nix
modify
save → failed to save → retry as sudo
on kde plasma, “policykit1 kde agent” will ask password
limitations:
need password on every “save file”
cannot create new files
git integration is not working
more comfortable is this solution:
for example
mkdir ~/etc
sudo mv /etc/nixos ~/etc/
sudo chown -R $(id -un):users ~/etc/nixos
sudo ln -s ~/etc/nixos /etc/
#code ~/etc/nixos/
codium ~/etc/nixos/
see also
Nixos-rebuild: Specifying a different configuration location
Github strategies for configuration.nix?