Cut the chicken fillet into small pieces at random.
Mix sour cream with table horseradish. (Horseradish is a matter of taste, you can put it more or less. I put 2 spoons.) Salt.
Sour cream should not be sour, fresh, from a trusted manufacturer. The final result and taste of the dish depends on its quality. But the percentage of fat content is not particularly important here.
Pour the chicken fillet with sour cream, mix well and put in a baking dish. Place in a preheated 190° oven and cook for 35-40 minutes.
Everything is ready! Serve immediately with rice garnish, pasta, and stewed vegetables.