I was able to build this from my nur repo here. What you could do is add the package to a separate .nix file and use callPackage.
stm32cubemx-4_27_0 = callPackage ./pkgs/stm32cubemx {};
replace ./pkgs/stm32cubemx with the location of your .nix file.
I wouldn’t suggest using overrideAttrs in this case but it is up to you. If you are installing multiple versions of the same project then it may be needed. I just discovered this with the jdk today.