Bake the potatoes: Preheat oven to 425F. Wash and dry them, rub with olive oil and salt, and bake on a sheet pan for 45 to 60 minutes until fork-tender.
Make the Chili: Heat the olive oil in a large skillet or Dutch oven over medium heat, saute the onion with a pinch of salt until softened, add the ground beef, and cook, breaking it apart, until browned.
Add the diced tomatoes, Worcestershire sauce, tomato paste, ketchup, garlic, chili powder, cumin, onion powder, garlic powder, and paprika; stir to combine.
Add the salt, beans, and broth; simmer gently, covered, for 5 to 10 minutes.
Finish the Chili: Stir in the corn flour, add the cold butter, and stir until melted and emulsified; simmer briefly until thickened.
Serve: Cool the potatoes slightly, slit them lengthwise, open them, and fluff the insides with a fork. Spoon the chili over the potatoes and top with cheddar and Greek yogurt or sour cream.