Although there is no Mailchimp element at the moment, you can still insert Mailchimp form into the page by using Custom code element.

First, you will need to create a Signup form in Mailchimp and get the embed code. You can follow this article.

In Zeno Editor, drag a Custom code element into the page, then paste the code into the Content HTML setting.

The Mailchimp form should appear correctly in Viewport.