Heat oil in large pot over medium heat. Add onion and cook until translucent, about 3-5 minutes. Add ground turkey and cook until browned, stirring occasionally, about 7 minutes.
Stir in remaining ingredients with the exception of shredded cheddar and sour cream. Reduce heat to low and simmer for 20-25 minutes.
If making ahead, cool and refrigerate overnight. Before the big game, transfer chili to a slow cooker and set to warm. Serve in bowl and top with shredded cheddar and sour cream.