In a small bowl, combine masa harina, chili powder, onion powder, garlic powder, seasoning salt, paprika, cumin, garlic salt, sugar, dried minced onion, and beef bouillon powder; stir until evenly mixed.
Heat a large nonstick skillet over medium-high heat and crumble in the ground beef. Cook, stirring and breaking up the meat, until fully browned.
Drain excess grease by transferring the browned beef to a colander, then return the beef to the skillet.
Add the prepared spice mix to the skillet with the beef and pour in 3/4 cup to 1 cup water; stir to combine.
Reduce heat to medium-low and simmer the beef mixture for about 20 minutes, stirring occasionally, until most moisture has evaporated but the meat is still moist; remove from heat.
Warm a clean skillet over medium heat. Place each tortilla in the skillet for about 30 seconds per side until warmed and pliable.
Stack warmed tortillas and keep them covered with a towel to retain heat while you finish assembling tacos.
Spoon about 2 tablespoons of the seasoned beef onto each tortilla, then top with shredded lettuce, shredded cheddar, and diced roma tomato. Add sour cream if desired.
Repeat to assemble remaining tacos and serve immediately with your favorite taco sauce.