Preheat oven to 375 degrees. Lightly spray a 7x11 casserole dish with cooking spray, set aside.
In a large skillet set over medium heat, add the olive oil. When the oil is hot, add the beef and break up. Add onions and seasonings, cook until the beef is browned. Pour in 1/3 cup of enchilada sauce to the pan and stir to combine. Remove from heat and set aside.
Pour the remaining enchilada sauce into a pie dish. Coat enchiladas one at a time, then fill with beef and a sprinkle of cheese. Roll up and place into the prepared baking dish. Repeat until all of the filling is gone. You may need one or two more tortillas depending on how full you fill them.
Pour leftover enchilada sauce over top, then sprinkle with remaining cheese, green onions, and olives.
Cover with aluminum foil and bake for 20 minutes, then remove foil and continue baking for an additional 10 minutes.
Remove from the oven and let rest for 10 minutes before serving. Sprinkle with cilantro, if desired.