You must go to my top 3 street food places.. damn tasty food bro....
Chache Di Hatti, Kamla Nagar
Juneja's, Amar Colony Market, Lajpat Nagar
Atul Chaat, Rajouri Garden
There are many but if you want to start a trail you can do it from somewhere near your location, like Nizamuddin (but only after things get better of course)
There are plenty of them, you just have to find one's that suits your taste. Let me suggest you some street food areas:
1. Jama Masjid
2. Nizamuddin
3. Kamla Nagar
4. Karol Bagh