I think this play is already conditionalized on whether the nginx role has run or not:

```
- name: Copying nginx config {{ site_name }}
  template: src={{ item }} dest=/etc/nginx/sites-available/{{ site_name }}
  first_available_file:
  - "{{ local_dir }}/nginx/templates/{{ site_name }}.j2"
  # seems like paths in first_available_file must be relative to the playbooks dir
  - "roles/nginx/templates/{{ site_name }}.j2" 
  notify: restart nginx
  when_set: $nginx_role_run
```