Peel the potatoes and cut them into ¾-inch cubes. Place them in a medium pot and add the chicken broth, plus enough water to cover the potatoes. Bring the liquid to a simmer over medium high heat, and partially over the pot, and simmer, adjusting the heat as necessary, until they are almost tender, but still a bit firm in the middle, about 6 minutes. Reserve 1/2 cup of the cooking liquid, drain the potatoes and set them aside.
Meanwhile, melt the butter in a large pot or Dutch oven over medium heat, and add the flour. Cook, stirring until the mixture turns golden, about 2 minutes. Slowly pour in the milk, whisking constantly. Continue whisking until the mixture is bubbly and smooth and starts to thicken a bit.
Whisk in the can of Campbell’s® Potato Soup, salt and pepper, garlic powder and cayenne. Add the partially cooked potatoes and the reserved cooking liquid and switch to a wooden spoon stirring until the potatoes are cooked through, about 5 to 8 more minutes. Remove from the heat and gradually whisk in two cups of the shredded cheese until the cheese has melted and the mixture is smooth.
Serve in bowls topped with sour cream, bacon, additional cheddar and chives.