Cook the Chicken: Heat olive oil in a skillet over medium heat. Season the chicken breasts with chipotle seasoning, salt, and pepper. Cook for about 6-7 minutes per side until golden and fully cooked. Remove and let it rest before slicing.
Prepare the Spread: Mix mayonnaise, sour cream (optional), and lime juice in a small bowl.
Toast the Bread: Butter the bread slices and toast them until golden brown in a skillet or toaster.
Assemble the Sandwich: Spread the creamy sauce on each slice of bread. Layer with sliced chicken, avocado, and melted cheese. Optionally, add fresh cilantro.
Grill the Sandwich: Grill the sandwich in the skillet over medium heat until crispy and golden, and the cheese is melted, about 2-3 minutes per side.
Serve: Cut in half, serve warm, and enjoy!