Ingredients

Sauce and Filling
1 1/2 tablespoons vegetable oil or corn oil
1 medium onion,chopped fine (about 1 cup)
3 medium cloves garlic, minced or pressed through garlic press (about 1 tablespoon)
3 tablespoons chili powder
2 teaspoons ground coriander
2 teaspoons ground cumin
1/2 teaspoon table salt
2 teaspoons granulated sugar
12 ounces boneless, skinless chicken thighs (about 4 thighs), trimmed of excess fat and cut into 1/4-inch-wide strips
2 cans tomato sauce (8 ounces each)
1/2 cup chopped fresh cilantro leaves
1 can (4 ounces) pickled jalapeños, drained and chopped (about 1/4 cup)
8 ounces sharp cheddar cheese, grated (2 cups)

Tortillas and Toppings
12 corn tortillas (six-inch)
Vegetable cooking spray
3 ounces grated sharp cheddar cheese (3/4 cup)
3/4 cup sour cream
1 avocado, diced medium
5 leaves romaine lettuce washed, dried, and shredded
2 limes, quartered

Directions

1. FOR THE SAUCE AND FILLING: Heat oil in medium saucepan over medium-high heat until hot and shimmering but not smoking, about 2 minutes; add onion and cook, stirring occasionally, until softened and beginning to brown, about 5 minutes. Add garlic, chili powder, coriander, cumin, salt, and sugar; cook, stirring constantly, until fragrant, about 30 seconds. Add chicken and cook, stirring constantly, until coated with spices, about 30 seconds. Add tomato sauce and 3/4 cup water; stir to separate chicken pieces. Bring to simmer, then reduce heat to medium-low; simmer uncovered, stirring occasionally, until chicken is cooked through and flavors have melded, about 8 minutes. The sauce should have also thickened a bit. Pour mixture through medium-mesh strainer into medium bowl, pressing on chicken and onions to extract as much sauce as possible; set sauce aside. Transfer chicken mixture to large plate; freeze for 10 minutes to cool, then combine with cilantro, jalapenos, and cheese in medium bowl and set aside.

2. Adjust oven racks to upper and lower-middle positions and heat oven to 300 degrees. Divide tortillas onto two baking sheets and spray tortillas lightly with vegetable oil spray. Turn them over and spray the other side. Place on upper and lower positions of the oven for 4 minutes to help soften and seal the tortillas so they are easier to work with and don't turn to mush. After the four minutes remove from the oven and set oven to 400 degrees.

3. Add 1/3 cup of filling to each tortilla. Roll each tortilla lightly and place next to each other in the pan. Once they are all in, pour the remaining sauce down the center of the pan and use a spoon to spread over the tortillas so that it covers all but the ends. Sprinkle the remaining cheese down the center.

4. Cover baking dish with foil. Bake enchiladas on lower-middle rack until heated through and cheese is melted, 20 to 25 minutes. Uncover and serve immediately, passing sour cream, avocado, lettuce, and lime wedges separately.

TO MAKE AHEAD: The sauce and filling can be prepared (step 1) up to 2 days ahead and refrigerated in an airtight container; however, the enchiladas should be assembled shortly before baking.