Difference of goods

Nil rated goods are those goods on which rate of GST itself is 0%
For e.g. Fruits, Foodgrains, Bindi, etc.

Exempted goods are generally those goods on which there is different rate of GST applicable but the same has been exempted by Govt for GST.
For e.g. Export of goods are exempt from GST.
Here even if your GST rate is 28 % on product, your sale shall be exempt as it is an export.

Hope it clarifies your query