MAKE AHEAD: After broiling, let the enchiladas cool for 30 minutes. Pack individual servings in freezer containers and freeze for up to 2 months. When ready to eat, thaw in the fridge overnight, or let stand at room temperature for 1 hour. Microwave, covered, on high for about 2 minutes. Or, place in an ovenproof container, cover with foil, and bake at 350° until warmed through, 15 to 25 minutes.