Pour the beans into a colander and look them over for any small rocks or other debris that does not belong and discard. Rinse the beans well and set aside.
In a pressure cooker over medium-high heat, add the sausage, crumbling it as it is added.
Cook the sausage, stirring often, until cooked through. (Watch the pot and make sure your sausage does not burn. You don’t want flecks of black char throughout your soup.) If your sausage renders a lot of fat, drain off all but 1 tablespoon of the fat.
Add the Italian seasoning and leeks; saute until softened, about 5 minutes.
Add the garlic and cook for another 30 seconds.
Add the stock, water, beans, bay leaves, salt and pepper according to taste. Be sure the liquid is flavorful since the beans will be absorbing some of this liquid. As long as your sausage is cooked through, you can taste the liquid and adjust seasonings as needed.
Lock the lid onto the pressure cooker and set the valve to high pressure. Once the pressure cooker has alerted you that it has reached internal pressure, set a timer for 20 minutes.
After the time has elapsed, allow the cooker to naturally release.
Carefully remove the lid once it is safe to do so, opening the lid away from you for safety.
Stir. Remove the bay leaves and discard. They have given their all.
Carefully taste for seasoning; it will be hot. Adjust according to tastes.
Add the chopped Swiss chard and stir to wilt.
An optional step is to add a touch of vinegar, white balsamic vinegar, or lemon juice to your soup. Start with a couple of teaspoons, taste and see if you’d like to add anymore.
Serve warm in bowls.