Mix flour and taco seasoning mix. Roll chicken in seasoning mix, then melted butter and then crushed tortilla chips. Place in a sprayed casserole dish.
Make cheese sauce. Saute 2 tablespoons onion in 1 tablespoon oil. Add 2 tablespoons flour and dash of salt. Stir in 1 can evaporated milk and 1/4 teaspoon hot pepper sauce. Bring to a boil and cook 1-2 minutes. Add 1 tablespoon lemon juice, 1 cup Monterey Jack cheese and 1/2 cup black olives. Cook until cheese melts.
Pour cheese sauce over chicken and bake for 50 minutes at 375-degrees. OLE!