Preheat the oven to 375 degrees F.
In a 2 ½ quart (or 9x13) baking dish, pour in ¼ of the carton of chili and using a rubber spatula, spread to evenly coat the bottom of the dish.
One at a time, place the tortillas in a dry (no oil) stainless steel skillet over medium heat and warm for about 30 seconds on each side to make them more pliable. Once warmed, place two slices of cheese on one side of each tortilla, gently roll it up, and place it seam side down in the baking dish.
Once all the enchiladas are rolled, pour the remaining chili over the enchilada and using a rubber spatula, spread to evenly coat the tops of the enchiladas. Top with the remaining shredded Monterey Jack cheese.
Cover tighlty with foil and bake, covered, for 15 minutes. Remove the foil and continue to bake until the cheese is golden brown and bubbly, 8 to 10 minutes.
Remove from oven and sprinkle with the green onions to serve, if using.