I make sweet potato tacos regularly.
dice (no need to peel) the SP and put in bowl of water and wazz in microwave until soft.
meanwhile, in a frying pan fry off any veg you fancy, I usually do courgette, onion, garlic, peppers, mushrooms, spinach etc, broccoli too.
add Mexican spice mix, or if you have them paprika, cumin, chilli powder etc to taste
add a squeeze of Tom puree
add the soft potatoes and fry.
get hard taco shells, lie on their side and put grated cheese on one side inside, whack in the oven until melted.
add lettuce/guacamole/salsa/jalapeños as preferred then add the mixed veg.
i find 2 enough for me, but husband needs 3. Our 2 year old will eat one deconstructed (minus the jalapeño m)