Yes, you can use your existing Mailchimp contact list and send emails through Mailchimp instead.
All registrations from Get Invited will then automatically be added to Mailchimp for you.
Click Settings on the main left hand menu
Click Connected Services
Click Connect Mailchimp Account
Enter your Mailchimp username and password
Mailchimp is now connected.
When you’re creating or editing your event, you’ll now see a new step for selecting which Mailchimp list you’d like to use.