These Cheesy Enchiladas Are My Ultimate Vegetarian Comfort Food

Name: These Cheesy Enchiladas Are My Ultimate Vegetarian Comfort Food
Ingredients: 12 ounces (340 g) sweet potato (about 1 large), peeled and cut into 1/2-inch pieces (about 2 1/3 cups); 4 ounces (113 g) poblano chiles, stemmed, seeded, and chopped (about 3/4 cup); 1 small yellow onion (4 ounces, 113 g), chopped (about 2/3 cup); 3/4 teaspoon Diamond Crystal kosher salt; for table salt use half as much by volume or the same weight; 1/4 cup (60 ml) extra-virgin olive oil, divided; 2 tablespoons plus 1 teaspoon (9 g) chili powder, divided; 1 tablespoon plus 1 teaspoon (9 g) ground cumin, divided; 1 1/2 teaspoons garlic powder, divided; 1/2 cup tomato paste (4 ounces, 113 g); 1 tablespoon minced chipotle chiles in adobo sauce; 1 teaspoon dried oregano; 4 cups (960 ml) homemade vegetable stock or store-bought low-sodium vegetable broth; 1 (15-ounce) can black beans, rinsed and drained; 1/2 cup (120 ml) sour cream, plus more for serving; 8 ounces (226 g) Monterey Jack cheese, shredded (about 2 cups), divided; 16 (6-inch) corn tortillas, warmed; Fresh cilantro, for garnish