Cut loaves in half horizontally and hollow out tops and bottoms, leaving 1/2" of bread in shells. Discard removed bread.
Combine oil and garlic; brush inside bread shells.
Sprinkle with 1 teaspoon Italian seasoning.
Layer bottom of each loaf with a fourth of the roast beef, mozzarella, basil, tomatoes, salami, artichokes, salad greens, chicken and onion. Repeat layers.
Season with salt, pepper and remaining 1 teaspoon of Italian seasoning and drizzle with remaining oil mixture if desired.
Replace bread tops; wrap tightly in plastic wrap.
Refrigerate for at least 1 hour before slicing. Enjoy!