Cut the pork into 2" square pieces.
In a skillet brown the meat on high with oil, until crisp edges form.
Remove husks from tomatillos and wash them with cold water and rub them so the stickiness is removed.
Slice the tomatillos, peppers, onions, and garlic, roast them In a cast-iron skillet or baking sheet on high heat or oven at 425° until blistered with black charred spots, and softened.
Place those ingredients with lime juice, cilantro, and salt in a food processor or blender and blend smooth.
Pour mixture into cooking pan of choice (pressure cooker, saucepan, or slow cooker)
Then place the meat in the cooking pot with green sauce and chicken stock.