It is in nature of man to believe in G-d; then why does science has no specific discipline to do that.
Because it can't. It's not nature of man for everyone (as I pointed out in the post above, I've met people who doesn't have the nature to believe in God).
If God was a scientific field, then God must by necessity be something we can study, like the natural things, which means that God must be part of nature. (Which means pantheism would have to be true.)
It shows that science is deficient and imperfect and human should not expect that science would guide one in all matters of life.
science is not deficient or imperfect, it's just a specific thing for something specific regarding our reality.
Cooking food is just as deficient and imperfect since cooking can't explain how to pain with pastels. (I cook, paint with pastels, etc, so I know, they're different fields of study).
Science focuses on nature and the things we can test, study, research, experiment on, recheck, etc. If you consider God to be part of that field, that God can be studied, probed, examined, tested, then you would be a pantheist. I never got the impression that you were?