Triggered emails can generate code snippets. You can use Corvid in Wix Stores and have it check if the checkout contains Item X - if so, run the snippet. =)
Tutorial for Triggered Emails: https://www.youtube.com/watch?v=MOU2v4gagAI
Support also has some info for Triggered Emails: https://support.wix.com/en/article/creating-a-triggered-email
More on Automation: https://support.wix.com/en/article/creating-a-new-automation