nx/packages/workspace/docs/run-script-examples.md

workspace.json:

"frontend": {
    "root": "packages/frontend",
    "targets": {
        "build": {
            "executor": "nx:run-script",
            "options": {
                "script": "build-my-project"
            }
        }
    }
}

nx run frontend:build

The build target is going to run npm run build-my-project (or yarn build-my-project) in the packages/frontend directory.

Caching Artifacts

By default, Nx is going to cache dist/packages/frontend, packages/frontend/dist, packages/frontend/build, packages/frontend/public. If your npm script writes files to other places, you can override the list of cached outputs as follows:

"frontend": {
    "root": "packages/frontend",
    "targets": {
        "build": {
            "executor": "nx:run-script",
            "outputs": ["{projectRoot}/dist", "{projectRoot}/docs"],
            "options": {
                "script": "build-my-project"
            }
        }
    }
}