Rinse the dried Great Northern beans under cold water.
Dice carrots, celery, and onion into ¼-inch pieces.
Slice Tuscan kale into thin ribbons, removing the tough stems.
Add beans, broth, beer, carrots, celery, onion, chicken, salt, pepper, garlic powder, thyme, and oregano to a slow cooker; stir to combine.
Cover and cook on low for 8 hours until beans are tender and chicken is cooked through.
Remove chicken thighs, shred with two forks, and return the meat to the slow cooker.
Mix tomato paste with 2 tablespoons hot water until smooth; stir into the soup.
Add kale ribbons and cook uncovered on low for 10 more minutes until tender.
Season with additional salt and pepper if needed, then ladle into bowls and serve hot.