Return the bacon to the pot and add the kidney beans, pinto beans, great northern beans, water, ketchup, sugar, mustard, and chili powder. Lock the lid into place and turn the valve to “sealing.” Select Manual or Pressure Cook and adjust the pressure to High. Set the time for 8 minutes. When cooking ends, let the pressure release naturally for 15 minutes, then turn the valve to “venting” to quick release the remaining pressure. Unlock and remove the lid and stir well before serving.