Preheat the oven to 400F. Lightly grease two large baking trays.
In a large, shallow bowl, whisk together the breadcrumbs, chili powder, salt, paprika, cumin, and garlic powder. Then, add the oil and stir until incorporated.
In another large, shallow bowl, whisk together the milk, flour, and lime juice until smooth.
From left to right, line up the sweet potato spears, milk batter, breadcrumb mixture, and greased baking trays.
Place a handful of the sweet potato spears into the batter, toss to coat, use a slotted spoon to shake off excess batter, and transfer to the breadcrumb mixture. Toss to coat and transfer to one of the greased baking trays. Repeat with the remaining sweet potato spears, leaving a bit of breathing room between each spear (if the pans get overcrowded, you'll risk steaming instead of crisping).
If extra crispy spears are desired, spray** the sweet potato spears with a bit more oil before baking.
Bake for 30 to 35 minutes, or until crisp and golden brown on the outside and fork-tender on the inside, tossing halfway through baking. Remove from the oven and let cool slightly.
Meanwhile, prepare the Avocado Garlic Aioli (recipe below) and gather/prepare the other toppings and garnishes.
Warm the tortillas just before assembling. Heat them, one at a time, in a small skillet over medium heat for 20 to 30 seconds per side or over an open burner flame set to medium-low.