Preheat oven to 350º F.
In a large bowl add the ground beef, egg, onion, bread crumbs, oregano, salt and pepper and stir to combine. Shape into 32 balls and arrange on a rimmed baking sheet. Bake for 25 minutes, uncovered. Remove from oven and discard the fat.
In a 3 1/2 to 4-quart slow cooker, add the crushed tomatoes, red pepper, brown sugar, dijon, chili powder, garlic powder, sriracha, nutmeg and season with salt and pepper. Stir to combine. Add the cooked meatballs, stirring gently to coat.
Cover and cook on low for 3-4 hours.
Place meatballs on toasted hoagie rolls and top with extra sauce and cheese. Serve immediately.