Add the oil, orzo, and garlic to a medium pot and cook over medium heat, stirring frequently, until golden, about 5 minutes.
Add tomato paste and taco seasoning, and cook until aromatic, about 1 minute. Add kale, drained beans, and broth. Increase the heat to medium high and simmer. Taste and season with salt as needed.
Cover, reduce heat to medium-low, and simmer until the orzo is tender, stirring occasionally as needed, about 15 minutes. Stir in the butter, then serve with sour cream and hot sauce.
