White Chicken Chili

Name: White Chicken Chili
Ingredients: 1/2 pound dried navy beans, picked over; 1 large onion, chopped; 1 stick (1/2 cup) unsalted butter; 1/4 cup all-purpose flour; 3/4 cup chicken broth; 2 cups half-and-half; 1 teaspoon Tabasco, or to taste; 1 1/2 teaspoons chili powder; 1 teaspoon ground cumin; 1/2 teaspoon salt, or to taste; 1/2 teaspoon white pepper, or to taste; two 4-ounce cans whole mild green chilies, drained and chopped; 5 boneless skinless chicken breast halves (about 2 pounds), cooked and cut into 1/2-inch pieces; 1 1/2 cups grated Monterey Jack (about 6 ounces); 1/2 cup sour cream; Garnish: fresh coriander sprigs; Accompaniment: tomato salsa