1.
Preheat oven to 350 degrees F (175 degrees C). Coat a large medium heat skillet with oil or cooking spray.
2.
Place cubed chicken breast into skillet and cook until the cubes are done and no pink is showing.
3.
In medium sized bowl mix enchilada sauce and cream cheese. Drop the heat to the skilet to low and add the mixture into the skillet with the chicken. Stir mixture for a few minutes. Add the corn(slightly defrosted), onions, olives, and mushrooms into the skillet and mix well. Add salsa slowly stirring constantly to a slightly thickened consistency. Turn off skillet.
4.
Take your 15x10x2 baking dish and spread a thin layer of the mixture into the bottom of the baking dish. Place on top of that 6 corn tortillas slightly overlapped. Then add half of the mixture on top of the tortillas and cover all tortillas. Add a final layer of tortillas. Then place the remaining mixture on top and cover all tortillas. Sprinkle grated Monterey Jack Cheese on top of the mixture.
5.
Bake on center rack of preheated oven for 20 - 25 minutes or until brown and bubbly. Take out of the oven and let rest for about 10 Minutes. Cut in squares and serve.