Yeah certainly its personnel choice, I dont know if you know hindusim. If you say Nag they belong to Shiv even Vishnu sleeps on the one and only biggest snake Adiseshan, still if you say Garuda then its Vishnu everybody remeber. Then y dont the makers made Nag worship some other God than Shiv y not Vishnu. They could made Vishnu he has the Adisehan the snake above all snake in entire universe. its traditional and how thinks going according to hindu mythology. And everybody knows ichchathari nag nagin is in Hindu mythology.
As for Jay, he is the VILLAN. The villan worshiping Bad God no problem at all, of course there is no Bad God but the WILL of God is not good thats the problem
No, I know about Hinduism.
There is a story behind that. All of the naags were cursed by their mother because they initially refused to listen to her. To save themselves they went up to Lord Shiva and he gave them their protection. Adi Sheshnaag personally had gone up to penance to become a servent of Lord Vishnu earlier than rest of the naags. Hence, majorly all naags worship Shiva. Also, there live in the lowest realms of the underworld (Or the hindu version of underworld called Paatal lok). In Paatal lok, Shiva is worshipped. All the demons and naags live in Paatal lok. One of the realms in Paatal is Naaglok. Since Vishnu is generally an adversary to demon (except a few of them), they don't worship Vishnu there generally. Because Shiva offered them his protection and put their naagraj Vasuki around his neck, they worship Shiva.