Begin by placing the sliced chicken breast evenly at the bottom of the crockpot.
Next, layer the sliced bell pepper and red onion on top of the chicken.
Carefully pour the can of diced tomatoes over the layered ingredients, then add the minced garlic and sprinkle the fajita seasoning over all the ingredients.
Season the mixture with salt and freshly ground black pepper according to your taste preference.
Place the lid on the crockpot and set it to cook on low heat for 6-8 hours or on high for 3-4 hours.
Once the cooking time is up, use a fork to shred the chicken directly in the crockpot.
To serve, take warm tortillas and spoon the fajita mixture into each one, adding your choice of optional toppings.
Notes
Serve with warm tortillas and optional toppings for a customizable meal.