Nil Rated Supply - Nil rated supply is the supply which is chargeable to nil rate of tax or 0% of tax. So goods or service which are said to be covered under nil rated supply are the ones which are chargeable to 0% GST.
Zero Rated Supply - Zero rated supplies are the ones which are executed under Section 16 of the IGST Act. It includes : Export of goods or services or both Supply of goods or services or both to a SEZ developer or SEZ Unit
Exempt Supplies - Exempt supplies are the supplies which are wholly exempt from tax under GST Act. Exempt supplies also include Nil rated supplies.