Preheat the oven to 350°F (175°C).
In a large bowl, combine the corn, mayonnaise, sour cream, lime juice, chili powder, cumin, smoked paprika, salt, garlic powder, and cayenne (if using); mix until evenly combined.
Pat the chicken breasts dry with paper towels and season both sides lightly with salt and pepper.
Heat a thin layer of oil in a nonstick skillet over medium heat. Brown the chicken 2–3 minutes per side until golden but not cooked through.
Arrange the browned chicken breasts in a casserole dish in a single layer.
Spread the corn mixture evenly over the top of each chicken breast.
Bake uncovered for 30–40 minutes, or until a meat thermometer inserted into the thickest part reads 165°F (74°C).
Remove from the oven and sprinkle with crumbled cotija cheese and chopped cilantro before serving.