Heat oven to 400 degrees F. Put chicken on rimmed baking sheet. Mix oil, lemon juice, salt and pepper. Brush about 1/4 cup over chicken.
The recipe calls for a quartered chicken with skin removed, but I used chicken breasts.
Roast until chicken is nearly done, about 20 minutes. While chicken is roasting, add onions to remaining oil mixture and toss to coat thoroughly.
Heat large skillet over medium-high heat. Add onion mixture and cook until onions are golden brown, 8 - 10 minutes.
Remove chicken from oven and arrange pitas on baking sheet. Scatter half of the onions onto pitas, and place a chicken quarter (or breast) on each. Roast 10 - 15 minutes longer, until chicken is done. remove from oven, top with remainng onions and sprinkle with pine nuts. Season to taste with salt and pepper and additional lemon juice, if desired.