In a large frying pan add the olive oil, chicken breasts and taco seasoning mix. Saute over medium heat until chicken is no longer pink inside. Set aside.
In large soup pot add the butter and onions and cook over medium heat until cook onions are translucent. Slowly add the flour, stirring continuously over medium low heat for 2-3 minutes. Don't let it burn.
Add the chicken broth to the flour onion mixture a little at a time stirring until thickened for 2-3 minutes over medium heat.
Add the Velvetta, shredded cheese, corn, black beans, enchilada sauce and salsa and cook over medium low heat until the cheeses are melted.
Add in the chicken and heat through but do not boil.
Serve and garnish with the Fritos/tortilla chips, sour cream and green onion.