Heat the tortillas briefly in microwave or oven, until soft and pliable.
Place two heaping tablespoons of chili con carne in the center of each tortilla.
Top with lettuce, scallions, and cheese.
Fold in the sides to make a parcel, making sure all the filling is enclosed.
Heat about 1 inch of oil in a large frying pan and when hot, lower in the chimichangas, folded side down first.
Cook 2 to 4 at a time, depending on the size of the pan.
Cook for 3 minutes and carefully turn over and cook another 3 minutes.
Using a slotted spoon, remove to a paper-towel-lined plate to drain. Repeat with remaining chimichangas.
Spoon the guacamole over the top of each and drizzle over the sour cream
Sprinkle on the chopped tomato and serve at once.