01 - Preheat the oven to 400°F. Lightly grease a 9x13-inch baking dish with olive oil or cooking spray.
02 - Pat the chicken breasts dry with paper towels. Drizzle with olive oil and season both sides evenly with ground cumin, garlic powder, salt, and black pepper. Arrange the seasoned chicken in a single layer in the prepared baking dish.
03 - In a mixing bowl, combine the diced tomatoes, finely chopped red onion, minced jalapeño, chopped cilantro, and fresh lime juice. Season with salt and pepper to taste, then toss gently to combine.
04 - Spoon the prepared salsa fresca evenly over each chicken breast, ensuring full coverage. Sprinkle the shredded Monterey Jack or mozzarella cheese generously over the top of each piece.
05 - Bake on the center rack for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the cheese is bubbling and lightly golden on top.
06 - Remove from the oven and let the chicken rest for 5 minutes. Garnish with sliced avocado, additional fresh cilantro, and lime wedges if desired. Serve hot.