Place chicken breasts in a bowl. Add olive oil, salt, pepper, garlic powder, paprika, chili powder and lemon juice. Mix well so every piece is coated. Let it rest for at least 15 minutes for better flavor.

Heat your grill pan or outdoor grill on medium-high heat. Lightly oil the surface to prevent sticking. Make sure the grill is hot before placing the chicken for a nice sear and smoky taste.

Place chicken on the hot grill. Cook each side for about 5 to 7 minutes. Press lightly to get grill marks. Check that chicken is fully cooked and juices run clear before removing.

Place a slice of cheese on each chicken piece during the last minute of cooking. Cover with a lid so the cheese melts smoothly and becomes soft and creamy.

Cut burger buns in half. Toast them lightly on the grill for 1 to 2 minutes. This gives a crispy texture and prevents sogginess when adding sauces and fillings.

Mix mayonnaise and ketchup in a small bowl. Wash lettuce and slice tomatoes evenly. Keep everything ready so you can quickly assemble the burger without losing heat from the chicken.

Place lettuce on the bottom bun. Add grilled chicken with melted cheese. Top with tomato slices and sauce. Cover with the top bun and press gently to hold everything together.

Serve the grilled chicken burger immediately. Enjoy while the chicken is juicy and the bun is warm. Fresh burgers always taste better right after assembly.