In a large skillet, heat the olive oil over medium heat. Add the diced chicken and season with chili powder, garlic powder, cumin, salt, and pepper. Cook for about 6-8 minutes, or until the chicken is cooked through and no longer pink in the center. Remove from heat and set aside.
In the same skillet, add the corn and cook for 3-4 minutes until heated through and slightly charred.
In a small bowl, mix together the mayonnaise, lime juice, and cayenne pepper (if using).
To assemble the bowls, start with a base of cooked rice. Top with the seasoned chicken, charred corn, sliced avocado, diced red onion, and crumbled cotija cheese.
Drizzle the lime mayonnaise over the top and sprinkle with fresh cilantro. Serve immediately.