Heat olive oil in a skillet over medium heat, then add diced onion and cook until soft, about 2–3 minutes.
Add minced garlic and cook for 30 seconds until fragrant.
Add ground beef to the skillet and cook, breaking it apart, until browned.
Drain excess grease if necessary.
Stir in Rotel tomatoes with their juices, chili powder, cumin, paprika, salt, and black pepper.
Simmer the mixture for 5–7 minutes until slightly thickened.
Reduce heat to low, then stir in shredded cheddar cheese until melted and creamy.
Warm tortillas in a pan or microwave until soft.
Spoon the cheesy beef mixture into tortillas, add optional toppings as desired.
Serve the tacos warm and enjoy.