failed nixd setup

lua/plugins/lspconfig.lua

@@ -16,6 +16,25 @@ return {
             },
           },
         },
+        -- nixd = {
+        --   mason = false,
+        --   settings = {
+        --     nixpkgs = {
+        --       'import (builtins.getFlake "/home/lyc/workspace/CS/OS/NixOS/flakes").inputs.nixpkgs { }',
+        --     },
+        --     formatting = {
+        --       command = { "nixpkgs-fmt" },
+        --     },
+        --     options = {
+        --       nixos = {
+        --         expr = '(builtins.getFlake ("git+file://" + toString ./.)).nixosConfigurations.k-on.options',
+        --       },
+        --       home_manager = {
+        --         expr = '(builtins.getFlake ("git+file://" + toString ./.)).homeConfigurations."ruixi@k-on".options',
+        --       },
+        --     },
+        --   },
+        -- },
         lua_ls = {
           mason = false,
         },