Spray 5- to 6-quart slow cooker with cooking spray. In 12-inch nonstick skillet, heat oil over medium-high heat. Add chicken to skillet; sprinkle with salt and pepper. Cook 4 minutes, turning once, until browned on both sides. Place chicken in slow cooker. Add water, broth, tomatoes, corn, enchilada sauce, onion, green chiles, cumin and chili powder.