Wash and score each sweet potato. Cook in your Instant Pot for about 20 minutes for a medium size. Smaller than 2 inches only cook for 15.
Meanwhile prep the praline filling: Melt butter, chop pecans if they are whole. In a small bowl, mix together brown sugar, flour, melted butter, and pecans.
When potatoes are tender, carefully cut along the horizontal and vertical of the top of the sweet potato. Tuck the skin under until the top of the sweet potato is exposed.
Use a fork to mash and separate the flesh of the potato. Place the sweet potatoes in a baking dish.
Fill each sweet potato with praline mixture. Add marshmallows to the top if desired.
Preheat the Vortex Air Fryer to 350°F. Put the sweet potatoes on the bottom rack. Bake for 5 minutes or until topping and marshmallows are golden brown.