Heat a large skillet over medium heat.
Add a neutral oil and allow to get hot, then add the diced onion and taco seasoning spices.
Cook for 5 minutes, then add in the ground beef. Cook until the taco meat is fully cooked through. If you want to keep the ground beef mixture warm, place it in oven-safe bowls and keep it in the oven in a warming setting.
Rinse rice until water runs clear.
Heat a medium saucepan and add the rinsed rice and liquid. Bring to a boil, then lower the heat to a simmer and cover with a lid. Cook until the liquid is completely absorbed. If you have one, you can use a rice cooker.
Prepare your other toppings: wash and cut lettuce, cut and saute veggies, slice mango and jalapeno, or any of your other favorite toppings.
Once you have your prepared toppings, you can serve them separately for a build-your-own-taco bowl or plate them up and enjoy them right away!