In a medium sized mixing bowl combine the diced tomatoes, sweet onion, jalapeno and cilantro.
Add the lime juice, lime zest, ½ teaspoon salt, garlic powder, sugar, and ¼ teaspoon black pepper and mix well to make a chunky salsa fresca. Allow to sit while preparing the chicken.
Place chopped chicken in an 8x8 inch pan and sprinkle with the olive oil, ½ teaspoon salt, ¼ teaspoon black pepper and cumin. Ensure an even spread of spices by gently mixing the chicken in the pan and then smooth the chicken into an even layer.
Pour the tomato mixture evenly over the chicken and top with the pepper jack cheese.
Bake for 35-45 minutes, until the chicken reaches an internal temperature of 165 degrees Fahrenheit.
Garnish with fresh cilantro (optional) and serve hot.