Cut the uncooked bacon into small pieces and place it in the pot along with the ground beef.
Add the diced onion and cook until the meat is no longer pink. Drain.
Add the water to the pot and deglaze by scraping off any stuck-on bits.
Add the molasses, apple cider vinegar, dry mustard, Worchestershire sauce, brown sugar, salt, garlic powder, and pepper.
Layer with the drained and rinsed navy, pinto, and black beans.
Layer the undrained pork and beans.
Do not stir. This is a very important step.
Close the lid and set to MANUAL/PRESSURE COOK for 7 minutes.
Allow the pot to naturally release pressure for 10 minutes.
Remove the lid, set the pot to SAUTE, and add the BBQ sauce and stir.
Notes
Stirring the ingredients in the Instant Pot before pressure cooking can result in a burn notice. Layer the ingredients so that the liquid can create pressure inside the pot.