Sudo nixos-rebuild switch gives error after installing home manager

1 
building the system configuration...
error:
       … while evaluating the attribute 'config.system.build.toplevel'

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:322:9:

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

       … while calling the 'seq' builtin

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:322:18:

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

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

       error: file 'nixos-config' was not found in the Nix search path (add it using $NIX_PATH or -I)

       at «none»:0: (source not available)

I was following tutorial by @librephoenix on youtube and i wanted to trim my system config but i could not rebuild after editing my system config