Heat 1 tablespoon olive oil in a large stockpot or Dutch oven over medium heat. Add chicken, and cook, stirring occasionally, until evenly browned, about 6-8 minutes; set aside.
Add remaining 1 tablespoon olive oil to the stockpot. Add onion, carrots and celery. Cook, stirring occasionally, until tender, about 3-4 minutes.
Add garlic and mushrooms, and cook, stirring occasionally, until tender and browned, about 5-6 minutes. Stir in thyme and oregano until fragrant, about 1 minute.
Stir in chicken stock and bay leaves; bring to a boil. Stir in orzo, rosemary and chicken; reduce heat and simmer until orzo is tender, about 10-12 minutes.
Stir in kale and cannellini beans until the kale has wilted, about 3-4 minutes.
Stir in lemon juice and parsley; season with salt and pepper, to taste.