Start by seasoning the chicken thighs with taco seasoning. You can use store-bought or make your own blend. Ensure the chicken is well-coated, then allow it to sit for at least 15 minutes to absorb the flavors.
In a large skillet or grill pan, heat 1 tablespoon of vegetable oil over medium-high heat. Add the marinated chicken thighs and cook for about 5-7 minutes on each side or until they are fully cooked and reach an internal temperature of 165°F (75°C). Once done, remove from heat and let them rest for a few minutes before slicing.
In the same skillet, add another tablespoon of vegetable oil if needed, and toss in the sliced onions and bell peppers. Season with 1/2 teaspoon of taco seasoning, salt, and pepper. Sauté for about 5-7 minutes until the vegetables are tender and slightly caramelized.
In a mixing bowl, combine the mayonnaise, pressed garlic, lemon or lime juice, and chipotle chili powder. Mix until smooth, and adjust the seasoning with salt and additional chipotle powder if desired.
Slice your rolls and layer the sliced chicken, sautéed vegetables, and a slice of cheese on each roll. If you prefer melted cheese, you can pop the assembled sandwiches under the broiler for a minute or two until the cheese is bubbly.
Spread the chipotle sauce generously on the inside of the top half of the roll, place it on the sandwich, and serve with your favorite sides. These Chicken Fajita Sandwiches are perfect for sharing!
