a phrase of hispanic origin used primarily by illegal immigrants and white kids who think that it's funny. Chinga la migra translates to "Fuck the police." Also "Fuck the border patrol."
Diego: What are you doing back in Juarez, Manolo?
Manolo: I got picked up by la migra, ese, the day before payday.
Diego: Man, Chinga la migra. Pinche putos.