In a medium bowl, combine the olive oil, chili powder, cumin, garlic powder, salt, and pepper. Add the chicken breasts and coat them evenly with the spice mixture. Let marinate for at least 15 minutes.

While the chicken is marinating, cook the corn in a skillet over medium heat until heated through and slightly charred, about 5-7 minutes. Remove from heat and set aside.

In a small bowl, mix together the mayonnaise, lime juice, and half of the cilantro. Set aside.

Heat a grill or grill pan over medium-high heat. Cook the marinated chicken for about 6-7 minutes on each side, or until fully cooked and the internal temperature reaches 165°F. Remove from heat and let rest for a few minutes before slicing.

To assemble the bowls, divide the cooked rice among four bowls. Top each bowl with sliced chicken, charred corn, crumbled feta cheese, avocado slices, and a drizzle of the lime mayo. Garnish with the remaining cilantro and serve with lime wedges.