Slow Cooker

Optional but recommended step: Heat oil in a large skillet. Add the ground beef and cook until no longer pink. Crumble the meat as it cooks. Drain grease before adding the browned meat to the slow cooker. 

1. Add all other ingredients to slow cooker. Stir to mix well.
2. Cook HIGH 3-4 hours or LOW 6-8.

Instant Pot

1. Turn on the IP and select sauté. Once hot add oil, ground beef and onion to the pot.  Cook 5-7 minutes, crumbling the meat as it cooks. You might need to do this in batches. Add garlic & cook an additional minute. Drain fat excess fat if needed.
2. Hit cancel and stir in the kidney beans, chili powder, cumin, paprika, salt, oregano, and pepper.
3. Pour diced tomatoes & diced tomatoes with green chilies on top. Do not stir.
4. Close lid and seal valve. Set high pressure and cook for 20 minutes. When done cooking, quick release pressure.
5. Stir & serve.