Pre-cook your sweet potatoes. I recommend in the crockpot, but you can also roast them in the oven at 350 for about 30 - 40 mins depending on the size of the potatoes.
Brown your ground beef in a skillet over medium-high heat. Once the meat is browned, drain the fat and return to skillet. Add taco seasoning and diced pepper while stirring and saute. You may add 1 -2 tbsp of water if needed to keep the meat from drying out.
To serve, use a fork to flatten the inside of a sweet potato slightly. Add the desired amount of meat filling and top with your choice of taco toppings.