Place chicken breasts between two sheets of plastic wrap and pound to ¾-inch thickness. Season with olive oil, garlic powder, smoked paprika, salt, and black pepper. Let rest for 10 minutes.

Grill the chicken breasts for 6-7 minutes on each side until cooked through and internal temperature reaches 165°F. Let rest before slicing.

Cook bacon in a skillet over medium heat until crispy, about 5-7 minutes. Transfer to paper towels to drain.

Combine mayonnaise, lime juice, and chopped cilantro in a bowl and whisk until smooth. Adjust seasoning as needed.

Toast bread slices until golden brown, about 2-3 minutes per side, optionally using leftover bacon fat for extra flavor.

Spread cilantro-lime mayo on toasted bread and layer with lettuce, tomato, grilled chicken, bacon, avocado, and red onion. Top with another slice of bread.