Using sauté setting... Add oil, onions, carrots, and celery to the pot. Cook for about 5 minutes (until onions are translucent and carrots begin to soften).
Add vinegar, garlic, thyme, and bay leaf - cook for 2 minutes, until the vinegar has evaporated.
Add broth, tomatoes, beans, salt, and black pepper to the pot. Mix well.
Finally, add kale to the pot and press down as much as possible so that most of the kale is submerged. Resist the urge to stir here since it is much more important that the beans are in broth.
Lock lid and cook for 15 minutes at high pressure. Once cook time is complete, quick-release pressure and remove the lid.
Remove thyme sprigs and bay leaf. Mix well.
Video
Notes
If you prefer to use canned beans (drained and rinsed), cook the soup for 4 minutes at high pressure. Then quick-release the pressure.
One variation I love with this soup is using frozen spinach instead of kale. But you don't need to cook the spinach, so I recommend adding it after you release the pressure. It will be perfectly cooked after sitting in the residual heat for a few minutes; just be sure to break up any clumps.
If you don't have kitchen twine to bundle the thyme, I like to add it to the liquid after all the other ingredients are mixed and ready to cook. This makes it easy to find and remove the sprigs.