Potato and Mushroom casserole

12 russet potatoes peeled,cut into about ½ inch slices
4 cups sliced mushrooms
1 onion thickly sliced
8 chicken thighs thickly sliced
4 cups shredded mozzarella cheese
salt and pepper
any seasoning for chicken
2-3 tablespoons mayonnaise
2 tablespoons light Olive oil

Heat oven to 400 degrees
Heat oil in a skillet or saute pan. Add mushrooms. Cook until all liquid is gone.
Season chicken with seasoning (add salt if seasoning has no salt)layer the chicken on the bottom of casserole dish.
In a bowl mix together potatoes, onions,salt,pepper and 2 tablespoons mayo.Transfer to the dish with chicken.
Mix mushrooms with 1 tablespoon of mayo and little bit of salt. Add the layer on top of the potatoes.
Cover with foil and bake for about an 1hr:15 -1hr:30 min. Remove foil.sprinkle cheese on top of the mushrooms and bake uncovered until all cheese is melted and has a light brown color