Heat olive oil in a large pot or Dutch oven over medium-high heat.
Add diced white onion and sauté until softened and translucent.
Add stew meat cut into 1-inch pieces and brown the beef for approximately 5–6 minutes, breaking it apart with a wooden spoon as it cooks.
Stir in minced garlic and cook for 1 minute until fragrant.
Add chili powder, cumin, smoked paprika, Italian seasoning, brown sugar, black pepper, and salt. Stir until the beef is evenly coated with the seasonings.
Stir in crushed tomatoes, drained and rinsed red kidney beans, and white vinegar.
Bring the chili to a simmer and cook for approximately 15 minutes, stirring every 5–7 minutes.
Stir in cornmeal and reduce the heat to low. Cook for an additional 10–15 minutes until the chili thickens.
Remove the chili from the heat and let it rest for 5 minutes.
Serve warm topped with cheddar cheese and sliced green onions.