Inject nestjs service from another module

You have to export the ItemsService in the module that provides it:

@Module({
  controllers: [ItemsController],
  providers: [ItemsService],
  exports: [ItemsService]
  ^^^^^^^^^^^^^^^^^^^^^^^
})
export class ItemsModule {}

and then import the exporting module in the module that uses the service:

@Module({
  controllers: [PlayersController],
  providers: [PlayersService],
  imports: [ItemsModule]
  ^^^^^^^^^^^^^^^^^^^^^^
})
export class PlayersModule {}

⚠️ Do not add the same provider to multiple modules. Export the provider, import the module. ⚠️

Let' say you want to use AuthService from AuthModule in my TaskModule's controller

for that, you need to export authService from AuthModule

@Module({
    imports: [
     ....
    ],
    providers: [AuthService],
    controllers: [AuthController],
    exports:[AuthService]
  })
export class AuthModule {}
  

then in TaskModule, you need to import AuthModule (note: import AuthModule not the AuthService in TaskModule)

@Module({
    imports:[
      AuthModule
    ],
    controllers: [TasksController],
    providers: [TasksService]
  })
export class TasksModule {}

Now you should be able to use DI in TaskController

@Controller('tasks')
export class TasksController {
   constructor(private authService: AuthService) {}
   ...
}