eway bill for nill rated interstate goods

yes however the e - way is not required for exempted goods 

way bill is required for only one type of exempted good that is deoiled cake

Yes , no need to Generate E-way when exempted Goods being transported. As per Notification 12/2018 CT ,
where the goods being transported are exempt from tax under notification No.
7/2017-Central Tax (Rate), dated 28th June 2017 , as amended from time to time and notification No. 26/2017-
Central Tax (Rate), dated the 21st September, 2017