Heat the olive oil in a large Dutch oven or soup pot over medium heat.
Add the onion, carrots, and celery. Cook for 5 to 6 minutes until softened.
Stir in the garlic, thyme, parsley, and oregano. Cook for 30 seconds.
Pour in the chicken broth and bring to a gentle boil.
Add the orzo and cook according to package directions, stirring occasionally to prevent sticking.
Once the orzo is nearly tender, stir in the shredded chicken.
Season with salt and black pepper.
Reduce the heat and simmer for 5 minutes until everything is heated through.
Stir in the lemon juice and fresh parsley.
Serve immediately while warm.