Chicken-Orzo Soup

INGREDIENTS

• 1 (32-ounce) container fat-free, less-sodium chicken broth, divided
• 1/2 cup uncooked orzo
• 2 teaspoons olive oil
• 2/3 cup coarsely chopped carrot
• 1/2 cup coarsely chopped celery
• 1/2 cup chopped onion
• 3/4 pound skinless, boneless chicken breasts, cut into 1/2-inch cubes
• 1 1/4 cups water
• 3 fresh parsley sprigs
• 1 fresh thyme sprig
• 4 cups fresh baby spinach
• 1 tablespoon fresh lemon juice
• 1/4 teaspoon salt
• 1/8 teaspoon black pepper