This recipe also comes from Janet Read, who grew up in St. Joseph and now lives in Georgia. She also sent me a recipe for her Corn Casserole. 
Her mother-in-law gave it to her when she got married.
1 large package king-size Fritos
1 stick butter or oleo
1 medium onion, diced
1 tall can evaporated milk
2 cans cream of chicken soup
2 cups cooked turkey (more is even better)
1 can Rotel
2 tablespoons flour
1/4 teaspoon paprika
Cheese, grated, the more the better (Janet uses Cheddar)
Saute onion in oleo, add flour and stir one to three minutes. Then add milk and cook until bubbly. Add undiluted soup, Rotel, paprika and meat. Cook and stir until thick. Put layer of half of Fritos in bottom of large baking dish, then all of creamed poultry mixture. Cover with the remainder of the Fritos. Grate cheese over top of Frito layer. Bake long enough to melt cheese in 350-degree oven, about 10 to 20 minutes. Do not brown!
Creamed mixture can be made ahead but the cheese will brown if you layer and heat at serving time. Add grated cheese after casserole is hot all the way through.
This doesn't reheat very well. If I am cooking for a smaller crowd, I usually only make about 1/2 the creamed mixture and bake in a smaller baking dish.