Roast the green tomatoes, chiles, onion, and garlic on a hot griddle. Blend with the broth and cilantro. Set aside.
Season the meat with salt and pepper and place the stainless steel inner pot inside the Instant Pot®. Press Saute and add the avocado oil to sear the meat on all sides. Add the nopales and purslane and brown a little. Then add the green sauce, integrate everything and taste the point of salt.
Close and lock the Instant Pot® lid. Make sure the steam release handle is turned to Sealing. Press Meat/Stew and set the time to 20 Minutes.
When done cooking, press Cancel and turn the steam release handle to Venting. Once all the pressure is released, open the lid and serve in a bowl with sufficient broth.