01 - Preheat oven to 400°F. Position the rack in the center of the oven for even heat distribution.
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 the bottom and sides are evenly greased to prevent sticking.
04 - Arrange the chicken breasts in the prepared baking dish in a single layer. Sprinkle both sides of each breast evenly with ground cumin, chili powder, and paprika, pressing the spices gently into the meat.
05 - Spoon the prepared salsa fresca generously and evenly over each seasoned chicken breast, allowing the juices to pool around the base of the dish.
06 - Distribute the shredded Monterey Jack or mozzarella cheese evenly across the top of each chicken breast, covering the salsa layer completely.
07 - Bake uncovered on the center rack for 25 to 30 minutes, until the chicken reaches an internal temperature of 165°F and the cheese is melted, golden, and bubbly.
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 and serve immediately.