Place the chicken breasts in the slow cooker.
In a medium bowl, mix together the diced tomatoes, cream of chicken soup, cream cheese, taco seasoning, garlic powder, onion powder, salt, and pepper until well combined.
Pour the mixture over the chicken in the slow cooker, ensuring the chicken is well coated.
Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the chicken is cooked through and easily shreds with a fork.
Once cooked, shred the chicken directly in the slow cooker using two forks and stir to combine with the sauce.
Warm the tortillas in a dry skillet or microwave.
Serve the shredded chicken in tortillas, topped with shredded cheddar cheese, cilantro, and any additional toppings like sour cream or salsa.