Season the pork with the salt and pepper and then add to the hot oil. Sear on all sides until golden brown, about 2-3 minutes per side.
Places the browned pork into the bowl of a slow cooker, followed by the poblano chiles, jalapeno, green bell pepper, tomatillos, yellow onion, garlic, ground cumin, dried oregano, cilantro, chicken broth/stock, and bay leaf.
Turn the heat to low and cook 6-7 hours, or until the pork is tender enough to be pulled apart with a fork.
Remove the pork and shred using a fork (you may need to wait for it to cool a bit).
In the meantime, remove the bay leaf from the slow cooker and discard. Either using an immersion blender directly in the slow cooker bowl or by transferring the slow cooker contents to a kitchen blender, puree the cooked peppers, onion, and chicken broth mixture until smooth. This is the chile verde sauce. Woohoo! Season to taste with any salt as needed.
To serve, layer a corn tortillas on a flat surface (I highly recommend looking for good quality corn tortillas - you may need to wrap in damp cloth and microwave for 10-20 seconds to make them pliable). Top the tortillas with a mound of the shredded pork, followed by 1-2 tbsp. of the pureed chile verde sauce. You can also top with additional chopped cilantro, diced red onion, and/or crumbled queso fresco. Feel free to squeeze some lime juice as well!