Return bison to the pot.
Add the Crushed tomatoes, Fire-roasted tomatoes, Tomato paste, Beef broth, Worcestershire, Sweet potato (if using).
Stir well.
Scoop the marrow from the bones and stir into the chili.
Bring to a simmer, then reduce heat to low.
Cover and cook 45–60 minutes, stirring occasionally (The longer it simmers, the more the flavors deepen).
Add ACV (or a splash of lime juice) at the end for brightness, if desired.
Taste and adjust the salt, pepper to taste.