Add the chicken breasts, celery, carrots, onion, chicken broth, bouillon cube, onion powder, garlic powder, minced garlic, and butter to your slow cooker.
1 ½ pounds boneless, 2 stalks celery, 3 carrots, 1 small onion, 9 cups chicken broth, 1 chicken bouillon cube, 1 teaspoon onion powder, 1 teaspoon garlic powder, 3 garlic cloves, 4 tablespoons butter