Season chicken with salt and pepper. Cut chicken into 1-inch chunks.

In large nonstick skillet, heat oil over medium-high heat and cook chicken and onion, stirring occasionally, 8-10 minutes or until chicken is cooked through. Stir in tomatoes and heat through.

In medium bowl, combine yogurt and dill until blended.

Spoon chicken mixture down the center of pita breads. Top with feta cheese. Drizzle yogurt sauce and fold in half to eat.