Build the Flavor Base: Heat the olive oil in a large skillet over medium-high heat (or directly in your slow cooker if it has a sauté function). Add the chopped red onion and cook, stirring occasionally, until softened, about 6–8 minutes.
Bloom the Aromatics: Stir in the minced garlic, tomato paste, ground cumin, sweet paprika, smoked paprika, and dried oregano. Cook for 60 seconds, stirring constantly, until everything is deeply fragrant.
Combine for Cooking: Transfer the onion and spice mixture to the slow cooker basin. Pour in the no-salt-added chicken broth and no-salt-added crushed tomatoes, then add the bay leaf. Stir well to combine. Arrange the chicken breasts in the liquid, ensuring they are mostly submerged.
Simmer Low and Slow: Secure the lid and cook until the chicken is tender and easy to shred. Cook on LOW for 7 hours for the most tender result, or on HIGH for 3 ½ hours.
Add Finishing Touches: About 30 minutes before the cook time is complete, stir in the rinsed chickpeas, chopped artichoke hearts, and rinsed Kalamata olives. Replace the lid and let it finish cooking.
Shred the Chicken: Carefully remove the cooked chicken breasts and place them on a cutting board. Discard the bay leaf. Using two forks, shred the chicken into bite-sized pieces.
Finish and Serve: Return the shredded chicken to the slow cooker. Stir in the chopped fresh parsley, fresh lemon juice, sea salt, and black pepper. Let the soup rest for 5 minutes for the flavors to meld perfectly. Serve hot, garnished with extra fresh parsley if desired.