Heat the oil in a large skillet or Dutch oven over medium heat. Add the diced onion and cook until softened, about 3 minutes.

Add the ground beef and cook, breaking it up with a spoon, until browned and cooked through. Drain any excess grease if needed.

Stir in the garlic and cook for 30 seconds, then add the taco seasoning, diced tomatoes with green chilies, and water. Mix well.

Add the chopped cabbage to the skillet and toss to combine. Cover and cook for 8 to 10 minutes, stirring occasionally, until the cabbage is tender but still slightly crisp.

Season with salt and black pepper to taste. Sprinkle the shredded cheddar cheese over the top and cover for 1 to 2 minutes, just until melted.

Remove from the heat and top with Fritos corn chips. Add optional toppings if desired and serve immediately.