Diced cooked chicken

1 can rotel tomatoes

1 can cream of chicken soup

1 lb. Velveeta cheese, grated or cut into pieces

1/2 onion chopped 

1 pkg. Doritos chips

Mix soup, Rotel, cheese and onion. 
Microwave until cheese is melted.  

Layer in a 9 x 13 pan: Doritos, chicken and then soup mixture on top.

Bake at 350 degrees for 30-35 minutes