Preheat your oven to 375°F (190°C).
Grease a 9-inch pie dish with olive oil.
In a mixing bowl, whisk together eggs and milk until well combined.
Season the egg mixture with salt and pepper.
Layer 2 tortillas at the bottom of the pie dish, overlapping slightly.
Spread half of the diced vegetables over the tortillas.
Pour a third of the egg mixture over the vegetables.
Sprinkle a layer of cheese on top.
Repeat the layering process with 2 more tortillas, remaining vegetables, egg mixture, and cheese.
Top with the last 2 tortillas and pour any remaining egg mixture over the top.
Bake in the preheated oven for 35-40 minutes, until the quiche is set and golden.
Allow to cool for a few minutes before slicing and serving.