Prepare the chicken. Salt and pepper the chopped chicken fillet to taste.
Prepare the casserole filling. Beat the eggs with a fork or whisk until smooth. Add mayonnaise. Mix thoroughly.
Prepare a baking dish. Lightly grease the bottom with vegetable oil. Place the chicken fillet on the dish. Add the filling. Place the tomatoes, cut into thin slices, on top.
Bake the casserole. Preheat the oven to 180 degrees. Bake the chicken casserole for 40 minutes.