Place a large skillet over medium-high heat and add the ground beef.
Cook the beef for 7 to 10 minutes, breaking it into small crumbles with a spatula, until no pink remains.
Drain the rendered fat from the skillet.
Add the chili powder, cumin, paprika, garlic powder, onion powder, salt, and pepper to the beef.
Pour in the water and stir to combine thoroughly.
Reduce heat to medium-low and simmer for 3 to 5 minutes until the liquid has reduced and formed a light sauce.
Warm the taco shells according to package instructions.
Distribute the beef mixture evenly among the 8 shells.
Top each taco with lettuce, cheese, tomatoes, and a dollop of sour cream.