Heat a 4- or 5-quart Dutch oven or heavy pot over medium heat. Add pancetta; cook 5 minutes, stirring often, until crispy. Add onion, carrots, and garlic; heat 3-5 minutes, stirring occasionally. Stir in tomatoes with juice, broth, salt, and pepper flakes; bring to a simmer. Stir in kale and beans; cook 5-7 minutes or until kale is tender.