Preheat the oven to 375°F (190°C).

In a large bowl, combine the chicken pieces, olive oil, chili powder, cumin, garlic powder, salt, and black pepper. Mix well to coat the chicken evenly.

Spread the chicken mixture on a baking sheet lined with parchment paper.

Bake in the preheated oven for 15-20 minutes, or until the chicken is cooked through and no longer pink.

Once the chicken is cooked, remove it from the oven and let it cool slightly.

In a mixing bowl, combine the baked chicken with black beans and corn. Stir until mixed well.

Cut the pita breads in half to create pockets. Stuff each pocket with the chicken mixture and top with shredded cheese.

Place the stuffed pita pockets back on the baking sheet and bake for an additional 5-7 minutes, or until the cheese is melted and bubbly.

Remove from the oven and let cool for a couple of minutes.

Garnish each pita pocket with chopped cilantro and a dollop of sour cream or yogurt before serving.