Cannot use NUR modules in NixOS flake

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1

Hi,
I am using flakes to configure my nixos and I am trying to modules defined in NUR. I followed the README and did the following:

I added the NUR overlay in the root with:

nixpkgs.overlays = [
...
        nur.overlay
...
]

then I try to add a module to my modules:

modules = [
...
(
  { pkgs, ... }:
    let
      nur-no-pkgs = import nur { nurpkgs = import nixpkgs { system = "x86_64-linux"; }; };
    in
    {
      imports = [ nur-no-pkgs.repos.iopq.modules.xraya ];
      services.xraya.enable = true;
     }
)
...
]

When I try to build I receive the following error:

error:
       … while calling the 'seq' builtin

         at /nix/store/qszplw617r895nbcprgyj139c9a3r0xs-source/lib/modules.nix:322:18:

          321|         options = checked options;
          322|         config = checked (removeAttrs config [ "_module" ]);
             |                  ^
          323|         _module = checked (config._module);

       … while evaluating a branch condition

         at /nix/store/qszplw617r895nbcprgyj139c9a3r0xs-source/lib/modules.nix:261:9:

          260|       checkUnmatched =
          261|         if config._module.check && config._module.freeformType == null && merged.unmatchedDefns != [] then
             |         ^
          262|           let

       (stack trace truncated; use '--show-trace' to show the full trace)

       error: cannot coerce a set to a string
2

Assuming this code:

modules = [
...
   nur-no-pkgs = import nur { nurpkgs = import nixpkgs { system = "x86_64-linux"; }; };

is embedded in flake.nix and “nur” is passed as an input here.

Try this:

modules = [
...
(
--  { pkgs, ... }:
++  { pkgs, config, ... }:
    let
--      nur-no-pkgs = import nur { nurpkgs = import nixpkgs { system = "x86_64-linux"; }; };
++      nur-no-pkgs = import config.nur { nurpkgs = import nixpkgs { system = "x86_64-linux"; }; };
    in
    {
      imports = [ nur-no-pkgs.repos.iopq.modules.xraya ];
      services.xraya.enable = true;
     }
)
...
]

If my initial assumption is wrong – can you link the whole config?