In a small bowl, mix paprika, cayenne, garlic powder, onion powder, oregano, salt, and pepper. Rub the seasoning evenly on both sides of each chicken cutlet.
Heat olive oil in a cast iron skillet or griddle over medium-high heat. Add chicken and cook for 5–7 minutes per side, or until fully cooked through. Cook in batches if needed. Let rest for a few minutes, then slice the chicken.
In a small bowl, mix mayonnaise, lemon juice, salt, and pepper. Adjust to taste.
Heat a skillet over medium heat and add butter. Add Texas toast slices and cook until golden brown on both sides. Set aside.
On one slice of toasted bread, layer sliced blackened chicken, Swiss cheese, and bacon. Add sliced tomato and lettuce. Spread lemon mayo on the second slice of toast, then place it on top of the sandwich.
Serve immediately and enjoy!