Slow Cooker Chicken Burrito Filling

Name: Slow Cooker Chicken Burrito Filling
Ingredients: 1 large onion (chopped); 1 red or green bell pepper (chopped); 2 jalapeno peppers (minced); 2 clove garlic (minced); 1 1/2 to 2 pounds boneless chicken thighs; 1 tablespoon chili powder; 1 teaspoon dried leaf oregano; 1 teaspoon ground cumin; 1/2 teaspoon ground coriander; 1 teaspoon salt; 1/2 teaspoon ground black pepper; 1 can (15 to 16 ounces) refried beans; 1/2 cup salsa (or enchilada sauce, plus more for serving); 1/2 cup Cheddar cheese (shredded or Cheddar Jack); 12 to 16 flour tortillas (8-inch)