Rinse the beans and place in a large container, cover with 1-2 inches of water. Leave on the counter to soak for 6 to 8 hours. If soaking overnight, place in the fridge to prevent the beans from fermenting.
When you are ready to start cooking, drain and rinse the soaked beans. Set the beans aside.
Heat the oil and butter in your pressure cooker with the lid off, when hot, add the onion and saute for a few minutes.
Add the garlic and bell peppers, saute to just soften them, a minute is fine.
Add the apple cider vinegar, Worcestershire sauce, cumin, chili powder, oregano, stir together.
Add the chopped bacon and stir in.
Add the chicken stock and beans, and stir together.
Place the lid on the pressure cooker, add the weight (jiggler). Turn the heat up to high. When the weight starts to move and release pressure, turn the heat to low or medium in order to maintain the jiggler moving and venting pressure (indicating you have full pressure.) Set your timer for 5 minutes.
When 5 minutes have passed, turn off the heat, and carefully move the pressure cooker to an unused burner and allow a natural release of pressure, basically, just let the pot sit there until you have indication of zero pressure, 15-20 minutes.
When the indication is zero pressure, pull off the weight (jiggler), then remove the lid. Taste the beans and adjust seasoning with salt and pepper as desired.
Serve as a side dish.