In a large skillet over medium-high heat, cook the ground beef while breaking it into small crumbles with a spatula until fully browned (approximately 7 to 10 minutes).
Drain the rendered fat from the skillet.
Add chili powder, cumin, paprika, garlic powder, onion powder, salt, and black pepper to the beef and stir to coat evenly.
Stir in the tomato sauce and water. Reduce heat to low and simmer for 5 minutes until the liquid has thickened and the meat is moist.
Warm the taco shells in a preheated oven at 350°F (175°C) for 5 minutes.
Assemble the tacos by portioning the beef mixture into the shells and topping with shredded lettuce, cheese, and diced tomatoes.