Heat the olive oil in a large skillet over medium-high heat. Add the ground beef and diced onion, breaking up the beef into small crumbles with a wooden spoon as it cooks. Sprinkle in 1 tablespoon (3 teaspoons) of chili powder, 1 teaspoon of cumin, salt, and pepper. Cook for 5-6 minutes until the beef is mostly browned with just a hint of pink remaining. Add the grated garlic and cook for 1 more minute until fragrant. Transfer everything to a plate and wipe out the skillet with a paper towel to remove excess grease.

Add the diced sweet potatoes, fire-roasted tomatoes with their juices, green chiles, water, remaining 2 teaspoons of chili powder, remaining 1 teaspoon of cumin, and a good pinch of salt and pepper to the same skillet. Stir everything together until well combined. Cover with a lid, reduce heat to medium-low, and simmer for 18-20 minutes, stirring occasionally to prevent sticking. The sweet potatoes are done when you can easily pierce them with a fork and they are tender all the way through.

Return the cooked ground beef mixture to the skillet and stir everything together, letting the flavors meld for about 1 minute. Sprinkle the shredded cheese evenly over the top, cover with the lid, and remove from heat. Let it sit for 1-2 minutes until the cheese melts. Garnish with chopped fresh cilantro if desired and serve immediately.