Building nightly

[SpieringsAE]

I'm working on the nightly setting (also target selection this is working properly).
But there is an issue. In the cargo_command() function
https:/slint-ui/cargo-ui/blob/dbf4777f198a5e12382bb23aca1a82bcc5d3b97a/src/cargo.rs#L471C1-L474C2
The env variable CARGO is used to get the instance of cargo to put at the front of the commando.
However this links to (on linux) /home/user/.rustup/toolchains/(stable-toolchain)/bin/cargo
This will give an error:

error: no such command: `+nightly`

        Cargo does not handle `+toolchain` directives.
        Did you mean to invoke `cargo` through `rustup` instead?

While the actual cargo (on linux) /home/user/.cargo/bin/cargo does work

Is there a way to circumvent this?
I see 2 options:

1. replace stable- with nightly- in the function when a nightly build is made
2. just use cargo and not the CARGO env variable, however this will not work for someone who doesn´t have cargo on their path, but who doesn't really?.