Mediterranean Lemon Chicken and Potatoes

Ingredients

• 1 1/2 lbs. boneless skinless chicken breasts, cut into 1-inch cubes
• 1 lb. yellow potatoes, cut into 3/4-inch cubes
• 1 medium onion, coarsely chopped
• 1/2 cup reduced-fat Greek or olive oil vinaigrette
• 1/3 cup quartered Kalamata olives (optional)
• 1/4 cup lemon juice
• 1 teaspoon dry oregano
• 1 teaspoon garlic salt
• 1/2 cup chopped tomato