Prepare the slow cooker: Spray the inside of the slow cooker with non-stick spray or lightly coat it with olive oil to prevent sticking.
Layer the ingredients: Place the diced onions, minced garlic, carrots, and celery at the bottom of the slow cooker.
Add the chicken: Lay the chicken breasts on top of the vegetables.
Incorporate the lima beans: Pour the frozen lima beans over the chicken, evenly distributing them.
Mix the broth: In a separate bowl, combine the chicken broth, Worcestershire sauce, thyme, smoked paprika, salt, and pepper. Stir well to blend the flavors.
Combine all: Pour the broth mixture over the chicken and beans, ensuring everything is well coated.
Cover and cook: Secure the lid on your slow cooker. Cook on low for 6-8 hours or on high for 3-4 hours.
Shred the chicken: Once cooked, remove the chicken breasts from the slow cooker. Use two forks to shred the chicken into bite-sized pieces.
Adjust seasoning: Taste the stew and adjust the seasoning with additional salt and pepper if desired.
Serve: Ladle the chicken and lima bean mixture into bowls and garnish with fresh parsley, if using.