Chicken Enchiladas

Name: Chicken Enchiladas
Ingredients: 1 tablespoon canola oil; 1 small onion finely chopped; 1 garlic clove minced; 1 jalapeño pepper finely chopped (remove seeds for milder flavor if desired); 1/4 teaspoon chili powder; 1 (28-ounce) can whole peeled tomatoes in purée; 1 teaspoon fresh lime juice; Coarse salt and freshly ground pepper; 8 (6-inch) corn tortillas; 12 ounces shredded cooked chicken (skin removed); 12 ounces shredded Monterey Jack cheese (4 loosely packed cups); 2 tablespoons pickled jalapeños minced (optional); Sour cream for serving (optional); Fresh cilantro leaves for serving (optional)