Once MailChimp is connected to Method:CRM, you can export all the contacts listed in the grid to a MailChimp list.
The export will respect the filter views and the current search results. So if you search for a particular tag, for example, a "VIP" tag, then only contacts tagged with "VIP" will be sent to MailChimp.
This article can help you understand on how to tag a contact in Method. Also, how to use Mailchimp with Method is covered in detail in this article.
Hope this help!