MailChimp & Sprout Forms
Currently, this may be a bit challenging to pull of with Sprout Forms v1.1.0

We do have several features and improvements in the works that will help you achieve this in the future though, including:


Full control over customizing the template HTML
The ability to customize the value of the name="" inputs
The option to submit form data to third-party URLs
Control over hidden fields


While I don't have a release date for you — the features above are currently under development.

I'll plan to revisit and update this post once we release those features.