Preheat the oven to 400F and move the rack to the middle position.
Cut the chicken breasts in half lengthwise so you have 4 thinner cutlets. Season both sides with garlic powder, chili powder, and salt & pepper.
Add the olive oil to an oven-safe skillet over medium-high heat. Once hot, add the chicken and cook for 3-4 minutes per side until lightly golden. Remove chicken from the pan.
Add the chopped onion to the skillet and sauté for 5 minutes until softened and lightly browned.
Stir in the Ro-tel tomatoes, black beans, corn, and smoked paprika. Heat through for a few minutes, scraping up browned bits from the pan.
Return the chicken to the skillet and spoon some of the tomato, bean, and corn mixture over the chicken. Sprinkle the Mexican cheese blend over everything.
Place the skillet in the oven for 5-7 minutes until the chicken is cooked through (165F) and the cheese is melted. Optionally broil for a few minutes to brown the cheese, watching carefully to avoid burning.
Top with fresh chopped cilantro if desired and serve immediately.