Soak beans overnight with 8-10 cups of water. Drain and rinse. Discard the soaking liquid. (see quick soak instructions in Notes if needed)
Add bacon to pressure cooking pot. Saute (brown) the bacon pieces until until crisp, about 5 minutes. Remove bacon with slotted spoon and put on a plate lined with paper towels.
Cook the onion in bacon drippings until beginning to turn translucent, about 3 minutes.
Add everything EXCEPT cooked bacon to the pot, stir to combine. Cook on high pressure for 35 minutes. Turn off heat and wait 10 minutes, then do a quick release of the remaining pressure
Check the beans to see if they are done. If they are undercooked, cook at high pressure for another 5 minutes. Do a quick release of the pressure.
Add cooked bacon. Simmer beans uncovered until the sauce is the desired consistency.
Notes
You can do a quick soak of the beans by bringing the beans to a boil in 8-10 cups of water, simmer 2 minutes and then let soak for 1 hour.