Install on fresh install of NixOS 25.11 "NixOS already has Nix installed"

[nick-walt]

$ sudo curl -sSfL https://artifacts.nixos.org/nix-installer | sh -s -- install
info: downloading installer
 INFO nix-installer v2.34.6
`nix-installer` needs to run as `root`, attempting to escalate now via `sudo`...
 INFO nix-installer v2.34.6

Welcome to the Nix installer!

Flakes are an experimental feature, but widely used in the community.
You can change this later in `/etc/nix/nix.conf`.

Enable flakes?

Proceed? ([Y]es/[n]o): n

Note: the experimental nix-command feature has been enabled.
Commands starting with `nix ` (e.g. `nix build`) are subject to interface changes.

NixOS already has Nix installed

Note: Looking at the request to proceed in the output above it is unclear if the Proceed? was referring to the Enabling of flakes or to continue with the installation process:

• if the Proceed refers to Enabling flakes the question could be phrased as:
  Enable flakes? ([Y]es/[n]o):
• if the Proceed? refers to continuing with the installation, the Enable flakes? question requires an input response as indicated above.

When attempting to force the install the result is an error:

$ sudo curl -sSfL https://artifacts.nixos.org/nix-installer | sh -s -- install -- force
info: downloading installer
 INFO nix-installer v2.34.6
`nix-installer` needs to run as `root`, attempting to escalate now via `sudo`...
 INFO nix-installer v2.34.6
Error: 
   0: Reading plan
   1: No such file or directory (os error 2)

Location:
   src/cli/subcommand/install/mod.rs:116

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.

Post install failure the Nix version is:

$ nix --version
nix (Nix) 2.31.4

[Mic92]

I have a look.