2 boneless, skinless chicken breasts, butterflied into halves (4 halves total)
2 tbsp. vegetable oil, divided
1 shallot, minced
2 cloves garlic, minced
1-2 tbsp. minced chipotle peppers in adobo sauce
1¾ cups chicken broth
5 cups tortilla chips, broken into large pieces
2 tomatoes, seeded and diced
4 oz. sharp cheddar cheese, shredded
2 tbsp. chopped fresh cilantro
Pat the chicken breast halves dry and season with salt and pepper. Heat 1 tablespoon of the vegetable oil in a 10-12 inch oven-safe skillet over medium-high heat. Add the chicken to the pan and cook until golden brown on both sides (chicken does not need to be fully cooked at this point.) Transfer to a plate and set aside.
Add the remaining oil, shallot, garlic, chipotle, and ¼ teaspoon of salt. Cook just until fragrant, about 30 seconds. Add the chicken broth, scrape the browned bits from the bottom of the pan, and bring to a simmer.
Stir in half of the tortilla chips. Nestle the chicken into the broth and cook over medium-low heat until cooked through (reading 160° F on an instant-read thermometer), about 10 minutes. Transfer the cooked chicken pieces to a cutting board and shred into bite-sized pieces when it is cool enough to handle.
Return the shredded chicken to the skillet with the tomatoes, ½ cup of the shredded cheddar cheese, and 1 tablespoon of the cilantro. Stir in the other half of the tortilla chips until they are incorporated and moistened.
Sprinkle the remaining cheese on top and place the pan under the broiler until the cheese is melted and browning, about 2-3 minutes. Top with remaining cilantro and serve, allowing the casserole to cool 5 minutes before serving.