01 - Preheat oven to 400°F. Position the rack in the center of the oven.
02 - In a mixing bowl, combine the diced tomatoes, red onion, cilantro, minced jalapeño, garlic, lime juice, kosher salt, and black pepper. Toss gently until well incorporated, then set aside to allow the flavors to meld.
03 - Lightly coat a 9x13-inch baking dish with olive oil, ensuring an even film across the bottom and sides.
04 - Arrange the chicken breasts in the prepared baking dish. Sprinkle both sides of each breast evenly with the ground cumin, chili powder, and paprika, pressing the spices gently into the meat.
05 - Spoon the prepared salsa fresca evenly over each chicken breast, distributing the mixture so every piece is well covered.
06 - Top each chicken breast generously with the shredded Monterey Jack or mozzarella cheese, spreading it over the salsa layer.
07 - Bake uncovered for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the cheese is golden and bubbling.
08 - Remove from the oven and let the chicken rest for 5 minutes to allow the juices to redistribute. Garnish with additional fresh cilantro if desired, then serve.