It's been a few years, but De Cero is great.

Personally, my favorite taqueria in Chicago is Big Star. I know it's not "authentic" - at least, it's not a place anybody from Mexico goes. But the tacos are amazingly good (pork belly!). The beer and whiskey are plentiful. You just have to deal with an infestation of hipsters and the fact that the place is perpetually crowded.