Heat vegetable oil in a large oven-safe skillet, over medium-high heat. Add onions and saute until soft. Add green chiles, diced tomatoes, leftover turkey and salsa. Adjust seasoning with salt and pepper, to taste. Top with tortilla chips and then cheese. Place skillet in oven and bake for about 20 minutes.
Remove from oven. Garnish with cilantro and serve immediately with side of sour cream.