01 - Set a grill pan or skillet over medium-high heat and allow it to come to temperature.
02 - Coat the chicken breasts evenly with olive oil, garlic powder, smoked paprika, salt, and black pepper. Place on the hot grill pan and cook for 6 to 7 minutes per side until the internal temperature reaches 165°F. Rest for 5 minutes, then slice into thin strips.
03 - In a mixing bowl, combine the mozzarella, cheddar, Parmesan, minced garlic, mayonnaise, and fresh parsley. Stir until all ingredients are evenly incorporated into a cohesive spread.
04 - Lay each flour tortilla flat. Divide the cheese mixture evenly among the four tortillas, spreading it across the center. Layer baby spinach, sliced tomatoes, red onion if using, and the sliced chicken over the cheese spread.
05 - Fold in both sides of each tortilla toward the center, then roll tightly from the bottom up to form a secure wrap.
06 - Heat a clean skillet over medium heat. Place each wrap seam-side down and grill for 2 to 3 minutes per side until the exterior is golden and the cheese has fully melted inside.
07 - Slice each wrap in half on a diagonal and serve warm.