Rinse and sort the navy beans. Place in a Dutch oven with 8 cups water. Bring to a boil for 2 minutes and remove from heat. Let stand, covered, until beans are softened, about 5 hours.
Drain the navy beans and discard the soaking liquid. Rinse beans and return to the Dutch oven. Add ham hocks, chicken broth, 4 cups water, onion, parsley, garlic powder, basil, black pepper, oregano, nutmeg, and bay leaves. Bring soup to a boil; reduce heat and simmer until beans are tender, about 1 1/2 hours.
Mix carrots, celery, and potato flakes into the soup until well combined. Cover and simmer until vegetables are tender, about 30 minutes more.
Take ham hocks from the pot and place on a cutting board until cool enough to handle. Remove meat from the bones and cut into bite-sized pieces. Return meat to the pot and warm through over medium heat, about 3 minutes.