Preheat the oven to 350 F. In a shallow dish, combine egg and milk. In another shallow dish, combine breadcrumbs and grated parmesan cheese.
Fully coat each chicken tender into the egg mixture, then fully coat into the breadcrumbs. Place onto a large greased baking sheet. Bake for 20-25 minutes.
Remove from the oven, and top evenly with marinara sauce, and sprinkle with mozzarella cheese. Bake for another 5-10 minutes.