Can I migrate from DAV College Chandigarh to PU main campus in my 2nd year of BA?

Yes, you can migrate from DAV College Chandigarh to PU main campus in your 2nd year of BA 

You just need to know about the requirements for doing so. These could include: marks required or seats vacancy, etc.

The students involved in the youth elections will be able to guide you. Try getting a hold of a person who is a party member. He may be able to get you in, by admission or by referral.

Also note that there could be a slight chance that in PU, the reference required has to be powerful or influential.