Hi, I am going for interview next to next week for my nanny visa application.can anyone here give me an idea on line of question that consul will be asking me.

Here are two (2) sites which maybe helpful in answering your question.

Immigration Option for Nannies (http://www.visalaw.com/05aug3/2aug305.html):

Questions to Ask Potential Nannies : Family Education (http://life.familyeducation.com/child-care/safety/40493.html)