Tenn. Code Ann. § 67-6-506

The commissioner, under emergency or other extraordinary conditions, may extend for not to exceed thirty (30) days the time for making any returns required under this chapter. There shall, however, be added to the amount of tax due, interest, as provided by § 67-1-801, from the regular statutory delinquency date until the date paid. No penalty will be assessed when the return is made and the full amount of taxes paid on or before the extended delinquency date. Any return and payment made subsequent to the extended delinquency date shall, however, be subject to penalty and any other late charges without regard to the period allowed by the extension.