If you reside outside the US on April 15, you get an automatic extension to file until June 15. Outside of regular tax requirements, digital nomads may also be subject to filing FinCEN 114, also known as FBAR (Foreign Bank Account Report). This is an informational report that must be filed if the aggregate of non-US financial accounts (checking, savings, brokerage, pension, etc) by June 30. Starting in 2017 (for 2016 reporting), the due date is being shifted to April 15, with ability to extend to October 15). If you have a bank account abroad.
An extension can be filed to extend your return Federal return until October 15. If you have US sourced income (perhaps you are a contractor for a firm in Massachusetts who issues you a 1099), you may still have state tax filing obligations.