If using leftovers, heat a large pot over medium heat. Add burgers and cook on each side until browned, then use a spatula or kitchen shears to break up into smaller pieces. If using fresh burgers, follow the instructions on the package, then proceed to this step.
To the same pot, add over onion and saute for 2-3 minutes.
Add all other chili ingredients to the pot, stir together, then let simmer until warmed through, about 10 minutes.
Serve chili with any toppings of your choice.