There are 3 governing situation in your question.

1)source of income - If your financial base is strong you can go for nlu otherwise au will suffice.

2)Targeted area -  If you want to go for upsc au will do its job but if you want to join corporate sector then nlu outshines au because au has no placement cell. 

3)You -  tier 1 university might be able  to provide you a headstart but in the long run it all comes down to you. 

hey pratyush,
in my opinion u should go for nlu, bcoz there competition level is good compared to other universities.
but all depend on your decision.
thnks!