Juice of 4 limes
6 tbsp. olive oil
1 tsp. dried oregano leaves
1 tsp. coarsely ground black pepper
1 tsp. salt
1 1/2 lbs. skinless boneless chicken breasts
2 lg. onions, halved lengthwise and cut into 1/4 inch slivers
2 pkgs. (7 oz. each) 6 inch corn or flour tortillas at room temp.
1 1/2 c. guacamole
8 oz. sour cream
2 ripe tomatoes, seeded and cut into 1/4 inch dice
1 1/2 c. grated Monterey Jack cheese

1. Combine the lime juice, 2 tablespoons of the olive oil, oregano, 1/2 teaspoon of the pepper and 1/2 teaspoon of the salt in a glass bowl. Mix well and add the chicken breasts. Cover loosely and marinate, turning occasionally for 2 hours.

2. Preheat the oven to 350 degrees F. and prepare hot coals for grilling.

3. In a shallow roasting pan, combine the slivered onions with the chicken breasts and marinade. Cover the pan with aluminum foil and bake until the chicken is just opaque, 15 to 20 minutes. Remove the chicken breasts to a platter and set aside.

4. Transfer the onions to a heavy skillet and add the remaining 4 tablespoons olive oil and any pan juices. Sprinkle with the remaining 1/2 teaspoon salt and 1/2 teaspoon pepper. Cook over medium heat, stirring often, until the onions are very soft and slightly browned, 15 minutes. Drain the onions and set them aside.

5. Place the chicken breasts over very hot coals and grill until they are cooked through but still moist, about 2 minutes on each side. Slice them into strips 3 inches long and 1/2 inch wide.

6. Lay 12 prepared tortillas on a large platter and serve along with the chicken, onions, guacamole, sour cream, tomatoes and cheese.