Preheat oven to 375 degrees.In a large nonstick skillet, heat 1 tb oil and add sliced onion and peppers. Add chili powder, oregano, salt and pepper and cook until softened, about 10 minutes.Warm tortillas in microwave (on plate with moist paper towel) for about 20-30 seconds. Start to assemble tortillas by first adding a small amount of cheese, sliced steak and vegetable mixture. Roll up tortillas to form a "cigar" and place into a baking dish sprayed with non stick spray. Once all enchiladas are assembled, pour sauce over all of the wrapped tortillas. Add a layer of cheese and place in oven. Bake for about 20 minutes or until cheese is melted and browned and sauce is bubbling. Garnish with chopped green onion if desired.