Combine chicken, Ro Tel, corn, black beans, kidney beans, chicken broth, garlic powder, cumin, chili powder and onion powder in a slow cooker.Stir.Cook on low heat about 6 hours or longer.About 30 minutes before serving, remove chicken from the soup and shred. Return chicken to your slow cooker.Add cream and salt and stir.In a cup, mix corn starch with warm water. Pour into slow cooker and stir until combined.Cook soup for approximately 30 more minutes until soup is warm and slightly thickened (you don't want it too thick.)Serve with tortilla chips, sour cream, shredded cheese and cilantro if desired.