Boggen, while surface water liability issues vary from state to state, a general rule - subject to lots of exceptions and interpretations of state specific laws from state supreme court to state supreme court - regarding redirection of surface water is that there may be liability for diverting water onto neighboring land.
Your neighbor's act of installing tile on your property is a pretty brazen act that may, at a minimum, amount to civil trespass if not criminal trespass in addition to providing a basis for you to assert a civil claim in the appropriate court in your jurisdiction.
If you don't already have an attorney lined up, let me know via PM here. I am pretty well connected with attorneys in every state via a couple of national organizations in which I am a member. I'd be happy to make some inquiries for you if you need the assistance.
Todd