Place the chicken breasts in the crock pot and season with garlic powder, onion powder, and black pepper.
Mix the cream of mushroom soup and sour cream in a bowl, then pour over the chicken.
Add the frozen mixed vegetables around the chicken.
Cover and cook on low for 4 hours until the chicken reaches 165°F / 74°C at the thickest part and shreds easily.
Shred the chicken with two forks, stir everything together, then sprinkle the shredded cheddar cheese on top and let it melt for 5 minutes before serving.