Heat vegetable oil in a large soup pot or Dutch oven over medium heat.
Add the chopped onion and sauté until translucent, about 8 minutes.
Add the ground beef to the pot with a pinch of salt and pepper, and cook until browned.
Stir in the tomatoes, beans (with their juices), green chilies, and garlic powder.
Bring the mixture to a simmer, then reduce the heat and let it simmer for 30 minutes, stirring occasionally.
Pour the chili into bowls and top with Fritos corn chips and shredded cheddar cheese.