In a large skillet over medium heat, heat the oil and brown the beef, breaking it up as you go (about 5 minutes).
While the beef is cooking, chop the onion and pepper and add them together with all remaining ingredients to a 4-Qt crockpot.
Next, drain off any excess fat and add beef to the crockpot and stir everything together.
Turn setting to low and cook for 6-8 hours.
Stir and test for salt, adjusting as needed. Serve with toppings as desired.