Chicken and Black Bean Nachos

Name: Chicken and Black Bean Nachos
Ingredients: 2 tablespoons safflower oil; 1 small white onion, chopped; 1 (15-ounce/425 g) can black beans, drained and rinsed; ½ teaspoon ground cumin; ¼ teaspoon dried oregano; Coarse salt and freshly ground black pepper; 12 ounces (340 g) tortilla chips; 2 cups (250 g) shredded cooked chicken; 1 ⅔ cups (10 ounces/284 g) shredded Monterey Jack cheese; 1¾ cups (16 ounces/454 g) salsa, store-bought or salsa verde; 1 avocado, pitted, peeled, and coarsely chopped; 1 jalapeño, thinly sliced; Sour cream, for serving