In a pot, whisk the flour with the milk. Place the pot on the stove and stir the mixture until it boils.
Add the butter and keep stirring until you get the desired sauce consistency.
Remove the béchamel sauce from the heat and set it aside.
In a pan, sauté the chicken pieces in olive oil over heat until they turn white.
Season the chicken with salt and black pepper. Add a quarter cup of water and let the chicken absorb it. Then, remove it from the heat and mix it with the boiled rice.
Grease an oven tray with a little oil and spread the chicken and rice mixture in it.
Pour the béchamel sauce over the rice. Sprinkle the shredded cheese on top.
Put the tray in a preheated oven at a medium temperature and leave it until the top is golden brown.
Serve the rice bake hot.