Preheat the oven to 400°F (200°C) and lightly grease a 9x13 inch baking dish with non-stick spray or olive oil.
Pat the chicken breasts dry with paper towels to ensure even browning and seasoning adhesion.
In a small bowl, whisk together the garlic powder, smoked paprika, onion powder, salt, and black pepper.
Rub each chicken breast with olive oil, then coat evenly on both sides with the prepared spice blend.
Arrange the seasoned chicken breasts in a single layer in the baking dish.
Distribute the sliced sweet mini peppers evenly over the top of the chicken breasts.
Place the baking dish in the oven and bake for 18-20 minutes.
Remove the dish from the oven and top each breast generously with the shredded mozzarella cheese.
Return to the oven for an additional 5-7 minutes, or until the cheese is melted and bubbly and the internal temperature of the chicken reaches 165°F (74°C).
Allow the chicken to rest for 5 minutes before serving. Garnish with fresh parsley.