Sauté onion and garlic in cooking oil until onion is clear. Add
tomato sauce and simmer a few minutes. Set aside.
In a small frying pan, immerse tortillas one at a time in 1/2 inch
of hot (but not smoking) vegetable oil for about thirty seconds,
turning once and then immediately removing to plate with spatula.
Tortillas must not get crisp but must remain pliable so that it
can be easily rolled up.
On each tortilla place pieces of shredded chicken breast and some
green chile. Roll up and place folded side down on serving plate.
Spoon hot tomato sauce over enchiladas and top with sour cream.