On the stovetop and using a pot and water, cook the tomatillos with the peppers for a few minutes on medium to low heat. For avoiding bitterness, do not overcook the tomatillos. Typically those cook in less than 10 minutes, and the tomatillos shouldn't burst.
When the tomatillos are ready, blend with the garlic, the cooked peppers, the fresh cilantro, some of the cooking water or homemade chicken stock (not too much), and the chicken bouillon. Set aside.
Season the pork meat with few drops of cooking oil, salt and pepper, and a pinch of cumin. This makes the pork meat more flavorful. Another option is to season with chicken bouillon before searing.
In the Instant Pot, using the sauteing mode sear the pork meat with some cooking oil. I like to use a stovetop griller for searing. That method adds more flavor to the meat, but the IP is a good option too.
Incorporate the tomatillo green sauce, the purslane, and the potatoes. Then season with chicken bouillon, pepper, cumin, and oregano.
Cook the purslane pork on the Instant Pot for thirty minutes on high, with the valve on. Let the pressure cooking do a natural release before opening.
Serve the pork stew with a side of white rice, black beans, and blue corn tortillas.