Preheat your oven to 220°C (430°F).
Grease a deep-dish pizza pan or a cast-iron skillet with olive oil.
Press the proofed dough evenly into the bottom and up the sides of the pan to craft a crust.
Arrange half of the mozzarella cheese at the base of the crust.
Spread the cooked Italian sausage, diced tomatoes, green bell pepper, onion, minced garlic, chopped basil, and 1 tsp of dried oregano evenly over the cheese.
Season the toppings with salt and pepper.
Pour the prepared tomato sauce over the pizza toppings.
Sprinkle the remaining mozzarella cheese on top.
Position the pizza in the preheated oven and bake for 25-30 minutes or until the crust turns golden brown and the cheese becomes bubbly and slightly browned.
Allow the pizza to cool for a few minutes before slicing.
Serve the pizza while hot and savor your homemade Chicago-style pizza!