Chile Relleno Casserole

Name: Chile Relleno Casserole
Ingredients: ½ tbsp neutral oil (canola, vegetable, or light olive oil); ½ large onion (roughly diced); 1 medium red bell pepper (roughly chopped); 1½ tsp Diamond Crystal kosher salt; 1 tbsp chili powder; ½ tbsp smoked Spanish paprika; ½ tbsp ground cumin; 1 tsp ancho chili powder; 1 tsp granulated garlic; ½ cup chicken stock; 1 14.5 oz can diced tomatoes; ½ tsp apple cider vinegar; 8 large poblano peppers; 6 oz Monterey Jack cheese (full fat, block cheese cut into 8 even-ish slices); 6 oz shredded mozzarella cheese (whole milk, full fat); 9 taco-sized flour tortillas (3 whole and 6 cut in half; corn tortillas will work too.); 1 batch ranchero sauce (see above)