Preheat the oven to 375°F (190°C). Lightly grease a skillet with cooking spray and heat it over medium heat.
In a mixing bowl, combine the minced garlic, garlic salt, ground black pepper, and cumin.
Coat each chicken breast evenly with the spice mixture.
Place the seasoned chicken breasts in the preheated skillet and cook, turning as needed, until browned on all sides and no longer pink inside, about 10–15 minutes total.
Transfer the cooked chicken to a 9×13 baking dish. Spoon the salsa evenly over the chicken, then sprinkle the shredded cheddar cheese on top.
Bake in the preheated oven for 15–20 minutes, until the cheese is bubbly and beginning to brown.