NDAs are typically not worth the paper they are written on, but consult a lawyer if you think it could help.

Fact of the matter is, the damage is done, there is no taking back what he said or did. Moving forward your choices are to let it go(fuck those guys anyway right!), or fight for something you probably won't get.

The process of getting lawyers and pursuing this in court is not an easy process, it will wear on you mentally, it will make you want to rip your fucking hair out in frustration and, in the end, probably nothing will come out of it.