Place the potatoes in a large pot and cover with salted water. Bring to a boil over high heat, then reduce heat to medium-low, cover, and simmer until tender, about 20 minutes. Drain. Meanwhile, heat a large Dutch oven over medium-high heat and stir in the sausage. Break up the sausage with a spatula, and cook and stir until the sausage is crumbly, evenly browned, and no longer pink. Remove the sausage to drain on a paper towel-lined plate. Stir the onion into the sausage drippings; cook and stir until the onion has softened and turned translucent, about 5 minutes. Stir in the kale, and cook and stir for 2 minutes. Pour in the chicken stock; stir in the sausage and potatoes, and return to a simmer. Stir in the hot sauce just before serving.