Heat the olive oil in a large pot over medium heat. Add the diced onion and bell pepper, and sauté until they begin to soften.

Add the minced garlic and ground beef (or turkey) to the pot. Cook, breaking up the meat with a spoon, until browned and cooked through.

Drain any excess fat from the pot.

Sprinkle the chili powder, cumin, paprika, dried oregano, cayenne pepper, salt, and pepper over the meat mixture. Stir well to coat the meat and vegetables with the spices.

Pour in the diced tomatoes (with juices) and tomato sauce. Stir to combine.

Add the beef or chicken broth to the pot, and bring the mixture to a simmer.

If using kidney beans, add them to the pot at this point.

Let the chili simmer for about 20-30 minutes, allowing the flavors to meld and the chili to thicken.

Taste and adjust the seasonings as needed.

Serve the keto chili hot in bowls, and top with optional toppings like shredded cheddar cheese, sour cream, chopped green onions, and chopped cilantro.