Nielles-l Ã s-Bl Ã quin is a commune . It is found in the region Nord-Pas-de-Calais in the Pas-de-Calais department in the north of France .
Nielles-l Ã s-Bl Ã quin is a commune in the Pas-de-Calais department in the Nord-Pas-de-Calais region of France .