Beat egg, vegetable juice, sour cream, Worcestershire sauce, sage, parsley, oregano, salt, black pepper, and hot pepper sauce in a large bowl. Stir in oats and allow to soak.
Melt butter in a skillet over medium heat; cook and stir onion, bell pepper, and celery until softened, about 5 minutes. Stir vegetable mixture, mushrooms, and turkey into oat mixture; shape into a loaf and transfer to a broiling pan.
Mix tomato sauce and chili sauce in a bowl; pour over turkey loaf.
Bake in the preheated oven until no longer pink in the center, about 1 hour. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).