In a large soup pot or Dutch oven, cook the bacon over medium heat until cooked but not crisp, about 5 minutes. Add the onion and garlic and cook, stirring, until softened, about 5 minutes. Add the potatoes and chicken broth and simmer until the potatoes are tender, about 15 minutes.
Meanwhile, pull the meat off the rotisserie chicken; discard the skin and bones. Add the chicken and white beans to the stew and cook until heated through. Just before serving, stir in the arugula and season to taste with salt and pepper.