Prepare the toppings: shred the iceberg lettuce, dice the tomato, and chop the cilantro; set out the shredded cheddar cheese, salsa, sour cream, and lime wedges.
Heat the vegetable oil in a large skillet over medium heat until shimmering, about 1 minute.
Add the onion and cook, stirring, until translucent and lightly golden, 4–5 minutes.
Stir in the garlic and cook until fragrant, about 30 seconds.
Add the ground beef and cook, breaking it into small crumbles, until browned and no longer pink, 5–7 minutes; season with the kosher salt and black pepper.
Sprinkle in the chili powder, ground cumin, paprika, and dried oregano; cook, stirring, until the spices are fragrant, 30–60 seconds.
Stir in the tomato paste and cook until it darkens slightly and coats the beef, about 1 minute.
Pour in the beef broth, bring to a simmer, then reduce heat to medium-low and cook, stirring occasionally, until the liquid reduces to a thick, saucy consistency, 5–8 minutes. The mixture should be moist but not watery.
Stir in the apple cider vinegar and remove from the heat.
Warm the corn tortillas in a dry skillet over medium heat until pliable and lightly charred in spots, 30–60 seconds per side; fill with the beef mixture and serve with the prepared toppings.