Preheat the oven to 325 degrees F (165 degrees C). Add oil to an oven-safe pot and place over medium heat. Add bacon and cook, stirring occasionally, until golden but not yet crispy, about 3 minutes.

Season stew cubes with salt and pepper. Place flour in a shallow bowl, and dredge cubes in flour, shaking off excess. Add to the pot and cook in bacon grease, mixing bacon in with beef until beef is browned on all sides. Pour in 1/2 cup beef broth to deglaze the pan and prevent sticking.

Add onion and garlic to the pot; cook and stir until onion is just translucent, about 3 minutes. Add tomato paste, chili powder, oregano, cumin, paprika, and coriander. Stir to coat onion and meat with spices.

Pour in Guinness; scrape up any bits on the bottom of the pot. Add tomato sauce and remaining beef broth; season with salt and pepper. Stir, then bring to a boil.

Transfer to the preheated oven and bake, uncovered, until chili is thick and meat is tender, 1 1/2 to 2 hours. Stir stew every 30 minutes to prevent scorching; add a small amount of water or broth if stew seems too dry.