Heat the oil in a 4 or 5 quart Dutch oven or soup pot over medium until shimmering. Add the sausage and cook until it begins to brown. Add the onions and bell pepper, and continuing cooking until the sausage has fully browned and the onions are translucent. Scootch the mixture aside and add a small glug of oil or broth to the cleared area. Spoon the paprika, chili powder, and cumin over the liquid and stir to create a paste. Let warm for 30 seconds or so; it should become fragrant. Sprinkle the masa harina (if using) over the sausage and onions, and stir everything together thoroughly.

Add the green chilis, corn, black beans, enchilada sauce, tomatoes and chicken broth and stir. Raise the heat to medium-high, and bring the soup to a low boil. Reduce the heat to medium-low, maintaining a gentle simmer for 15 minutes. Reduce heat to low to keep it safely warm until serving.

Meanwhile, spoon the Greek yogurt into a small bowl. When the soup has finished simmering, add a half cup of the soup liquid to the the Greek yogurt and stir well, then add the yogurt immediately to the soup pot and stir to combine. (This prevents the yogurt from "breaking" in the hot soup.) Squeeze half of the lime over the soup, stir, and taste. Add more lime, if desired, as well as salt (if needed).

If you have the time, make this soup ahead of time, cool, and stash in the refrigerator for the day, or overnight. This lets the flavors in the soup marry, and creates a very flavorful and thick soup.

To serve, ladle into bowls and top with your favorite garnishes.