Heat olive oil in a large skillet, add onions and sautee until almost tender.
Add ground beef to brown, adding green chiles when beef is about halfway done
Add burrito seasoning according to directions on packet
In a 9x13 pan, spread a small amount of enchilada sauce to keep tortillas from sticking
Place 6 tortillas on top of the sauce, top with 1/3 beans, then 1/3 meat mixture, then 1/3 of one can of sauce, then 1/3 cup cheese and 1/4 of the olives. Repeat this process until all the meat and beans have been used.
Place a final layer of 6 tortillas on top, cover with second can of sauce, then remaining 1 cup of cheese and remaining black olives.
Spray a piece of aluminum foil large enough to cover pan with non-stick cooking spray to avoid cheese sticking to foil.
Cover pan with foil and bake for 25 minutes
Remove foil and bake another 10 minutes or until cheese is bubbly.