Brown beef in a stockpot, stirring until it crumbles and is no longer pink; drain. Return beef to pot.
Rinse and drain pinto beans, corn, and green beans. Stir pinto beans and next 8 ingredients into beef; bring to a boil. Reduce heat; simmer 30 minutes.
Cut tortillas into 1/4-inch strips. Place on a baking sheet; coat with cooking spray. Sprinkle with salt.
Bake at 400° for 5 to 8 minutes. Ladle soup into bowls, and top with tortilla strips.