The "Error: Cannot find module '@nestjs/common'" error is a common issue that can occur when developing Nest.js apps. This error occurs when the Node.js runtime is unable to find the @nestjs/common module, which is a required dependency for the @nestjs/typeorm module.

There are several possible causes of this error, including:

The @nestjs/common module is not installed in your project.
There is a problem with the module path in your project's dependencies.
To fix this error, you can try installing the @nestjs/common module by running the npm install @nestjs/common command in your terminal. If the @nestjs/common module is already installed, you can try deleting the node_modules directory and re-installing your project's dependencies by running the rm -rf node_modules and npm install commands.

If you are still having problems after trying these steps, you may want to check the documentation for the @nestjs/typeorm module or seek help from the Nest.js community.