Shred the rotisserie chicken, discarding the skin and bones. Dice the onion and bell pepper, mince the garlic, drain the beans, thaw the corn, and cut the tortillas into 1 1/2-inch pieces.

Heat the neutral oil in a 12-inch (30 cm) deep skillet over medium heat. Add the onion, bell pepper, and salt. Cook for 5 to 6 minutes, stirring occasionally, until the onion is translucent and the pepper has begun to soften.

Add the garlic, chili powder, cumin, and oregano: Cook for 30 to 60 seconds, stirring constantly. The mixture should smell fragrant, but the garlic and spices should not darken significantly.

Pour in the enchilada sauce and chicken broth: Stir well, scraping the bottom of the skillet to release any browned seasoning. Bring the mixture to a gentle simmer.

Stir in the shredded chicken, black beans, and corn. Cook for 3 to 4 minutes, stirring occasionally, until everything is evenly coated and beginning to heat through.

Add the tortilla pieces and gently fold them into the filling. Simmer uncovered for 4 to 5 minutes, stirring carefully once or twice. The tortillas should soften and absorb some sauce while remaining visible as separate pieces.

Stir 1 cup (115 g) of the shredded cheese into the skillet. Cook for about 1 minute, until the cheese melts and the sauce looks creamy. The mixture should be thick and spoonable rather than soupy.

Sprinkle the remaining 1 cup (110 g) cheese evenly over the surface. Reduce the heat to low, cover the skillet, and cook for 3 to 4 minutes, until the cheese is completely melted. The center of the skillet should reach 165°F (74°C) because the cooked chicken is being reheated.

Remove the skillet from the heat and let it rest uncovered for 5 minutes. This allows the sauce to thicken slightly. Top with sliced scallions and cilantro, if using, and serve with sour cream.