(If using canned chicken skip this step)Season 2 pounds boneless skinless chicken breasts with 1 teaspoon salt and ½ teaspoon black pepper. Heat a large soup pot over medium-high heat and add 1 tablespoon olive oil. Sear the chicken breasts for 2 minutes per side, until golden brown but not fully cooked. Remove from the pot and set aside.
In the same pot, add the remaining 1 tablespoon olive oil. Add the diced onion, 1 cup sliced carrot, and ½ cup sliced celery. Cook 4-5 minutes, stirring frequently, until the vegetables begin to soften.
Stir in 1 cup white rice, 1 tablespoon grated ginger, and 1 tablespoon minced garlic. Toast for 2-3 minutes, stirring constantly, until fragrant.
Return chicken to pot. Pour in 8 cups reduced sodium chicken broth and season with 1 teaspoon dried thyme and 1 teaspoon dried oregano. Bring the soup to a simmer, then reduce the heat to medium-low. Simmer for about 15 minutes, or until the chicken is cooked through.
Use tongs to remove the chicken from the pot and transfer it to a cutting board. Shred the chicken using two forks, then return it to the pot.
Cook for an additional 5 minutes, until the rice and vegetables are tender.
Remove from heat and stir in ¼ cup lemon juice. Season with additional salt and pepper to taste.
