In a small bowl or measuring cup, whisk together yogurt, lemon juice, oregano, and salt for a marinade for the chicken.
To marinate the chicken, place it in a large bag and pour the marinade over the chicken, tossing to coat. Place in the refrigerator for at least 30 minutes & up to 4 hours.
Once the chicken is marinaded, remove from the marinade and discard the marindade. Place the chicken on a heated grill or grill pan.
Grill for 5-6 minutes per side, or until the chicken reaches 165 degrees F internally.
Slice or shred the chicken. Then in a small bowl mix together diced tomatoes, onions, parsley, and salt with lemon juice.
Warm a pita and then top with lettuce, chicken, tomato and onions, and tzatziki sauce.
This chicken is DELICIOUS! I make it weekly. We serve it with naan bread. The recipe makes enough for us to have more throughout the week. SOOOO good!