In a large skillet, heat the olive oil over medium heat. Add the chopped onion and sauté for about 3-4 minutes, until translucent. Then, add the minced garlic and cook for another minute until fragrant.
Increase the heat to medium-high and add the ground beef to the skillet. Cook, breaking it up with a wooden spoon, until browned and cooked through, about 5-7 minutes. Drain excess fat if necessary.
Stir in the chili powder, ground cumin, oregano, garlic powder, onion powder, smoked paprika, Kosher salt, cayenne, and black pepper. Mix well to evenly coat the beef with the spices.
Sprinkle the flour over the seasoned beef and stir to combine. Then, add the can of Ro-tel, including the juices, and the beef broth. Stir everything together and bring to a simmer.
Reduce the heat to low and let the mixture simmer for about 10-15 minutes, allowing the flavors to meld together and the sauce to thicken slightly.
In a separate skillet, heat a small amount of vegetable oil over medium heat. Fry the corn tortillas one at a time for about 30 seconds on each side until they are golden and pliable. Drain on paper towels.
To assemble, spoon a generous amount of the beef filling onto each tortilla. Top with shredded cheddar cheese, lettuce, and diced tomatoes. Serve with salsa on the side.