1. Start by heating a large, heavy-duty pan over high heat. Season the chicken breasts with salt and pepper. Add 1 tablespoon of olive oil to the pan, then cook the chicken for 5-6 minutes per side, or until fully cooked. Remove the chicken from the pan and let it rest before dicing.

2. In the same pan, heat the remaining 1 tablespoon of olive oil. Add the onion, bell peppers, and garlic, cooking for 2-3 minutes until softened. Stir in the diced tomatoes and fajita seasoning, cooking for another 2 minutes. Dice the cooked chicken and return it to the pan, stirring until fully combined.

3. Heat 1 teaspoon of oil in a clean pan over medium heat. Place two tortillas in the pan and spread 1 teaspoon of sour cream on one side of each tortilla. Top with shredded cheese, sliced avocado, the chicken mixture, a squeeze of lime, and a sprinkle of minced cilantro. Fold the tortillas in half to form a half-moon shape. Cook for 2-3 minutes per side, until the tortillas are crispy and golden, and the cheese is melted. Repeat with the remaining tortillas.