WooCommerce User Registration + Mailchimp

I have a WooCommerce site setup with the WooCommerce Mailchimp plugin but that plugin only allows me to target a specific WooCommerce function to send the data over.

My customer wanted me to add a registration page where their customers could register for an account before checking out. That form is where I’m having issues triggering the data to be send to Mailchimp via their API.

Has anyone ever had to do this before?