Spray crockpot with non-stick spray (helps with clean-up).
Place chicken breasts on bottom of crockpot, in a single layer and season with salt and pepper.
Layer the onion, bell peppers, and zucchini on top of chicken.
Sprinkle the minced garlic over the vegetables.
Layer the cannellini beans over the garlic.
Top with the two cans of fire-roasted tomatoes and Italian seasoning. Add additional pepper, if desired. I don't add extra salt.
Cover and cook on low for 4-6 hours until the chicken is cooked through. Shred the chicken when it's done, if desired and give it all a good stir. Serve with fresh basil on top, if desired. You can leave the chicken breasts whole, if desired and serve that way.
Serve over rice or as is.