Chicken Taco Nachos

Name: Chicken Taco Nachos
Ingredients: 2 Tbs. lard, bacon drippings or canola oil; 1/2 white onion, finely chopped; 3 garlic cloves, minced; 1 tsp. ground cumin; Kosher salt and freshly ground pepper; 2 cans (15 oz./470 g each) black beans, rinsed and drained; 3/4 cup (6 fl. oz./180 ml) low-sodium chicken broth; 1 1/4 lb. (625 g) boneless, skinless chicken breasts; 2 tsp. canola oil; 2 tsp. ground cumin; 2 tsp. chili powder; 1/2 tsp. kosher salt; 6 oz. (185 g) tortilla chips; 6 oz. (185 g) Monterey jack cheese, shredded; 2 ripe tomatoes, diced; 1 ripe avocado, pitted, peeled and cut into 1/2-inch (12-mm) cubes; 1/2 cup (4 oz./125 g) sour cream