In a medium-sized skillet, place ground chuck and minced garlic.
Heat over medium-high heat, stirring frequently with a wooden spoon and breaking up large chunks of meat, until meat is browned.
Transfer meat and garlic to a colander and drain off and discard fat.
Return skillet to heat.
Add chopped green chilies, undrained whole peeled tomatoes, chili powder, salt, and pepper to meat and garlic in skillet.
Mix well with a wooden spoon and cook over low heat uncovered for about 30 minutes or until most of moisture has evaporated from the meat mixture.
While meat mixture is cooking, break apart and wash and dry lettuce, using a lettuce spinner. Tear into bite-sized pieces. You should have about 2 quarts or 8 cups of lettuce greens. Set aside. Refrigerate if not using right away.
Shred cheddar cheese and set aside.
Cut out and discard core of tomato. Chop tomato coarsely.
Wash scallions and trim off and discard root ends.
Chop or slice enough scallions to yield about 1 cup.
Remove meat mixture from heat and cover to keep warm and set aside.
Just before serving, place lettuce in a large chilled bowl and arrange tortilla chips around outer edge.
Top lettuce with meat mixture and sprinkle cheese, scallions, chopped tomato, and sliced olives around meat mixture.
Top with a dollop of sour cream garnished with scallions and hot red peppers.