Heat vegetable oil in a large skillet over medium-high heat.
Add the chopped onion and cook for 2-3 minutes until softened.
Add the minced garlic and cook for 30 seconds until fragrant.
Add the ground beef to the skillet and cook, breaking it apart with a spatula, until browned and cooked through, about 6-8 minutes.
Drain excess fat from the skillet if necessary.
Stir in chili powder, ground cumin, smoked paprika, dried oregano, salt, and black pepper.
Add the tomato sauce and stir to combine. Reduce heat to medium-low and simmer for 3-4 minutes to let the flavors meld.
While the beef mixture simmers, warm the corn tortillas in a dry skillet over medium heat for about 30 seconds on each side or wrap them in a damp paper towel and microwave for 20-30 seconds.
To assemble the tacos, spoon the seasoned ground beef evenly onto each tortilla.
Top each taco with shredded lettuce, diced tomatoes, shredded cheddar cheese, chopped cilantro, and a dollop of sour cream.
Serve immediately with lime wedges on the side for squeezing over the tacos.