The incident in Times Square in which a car apparently had something that might have been a bomb that was supposed to explode in order to create chaos was thwarted by the sharp eyes of a vendor. I hate to tell you Taliban guys, but there are vendors and hustlers all over Times Square and if you attempt to hustle in on their territory, watch out for an explosion, and it will not be a bomb. Times Square hustlers are organized, they keep a sharp look on what is happening on the streets, and have the muscle to make you guys wish to be back on the hills of Afghanistan.
Let me suggest a much simpler plan if your goal is chaos creation. Get in a few cars and cross the George Washington bridge from two directions. Just have the cars break down and you have chaos reigning for miles around. There is no need to hurt anyone or blow yourselves up, just a broken down car or so on major highways and New York City will be paralyzed for days. It is inexpensive and the good news is that the New York City police will quietly tow you away to break down elsewhere.