Preheat oven to 425°F. Line a large rimmed baking sheet with a silicone mat or parchment paper. Set aside.

In a large bowl, add the diced potatoes and canola oil. Toss to fully coat the potatoes with the oil.

In a small bowl, stir together the all-purpose flour, cornstarch, taco seasoning, salt, and black pepper.

Add the seasoning mixture to the potatoes and gently toss them to coat evenly.

Spread the seasoned potatoes in an even layer onto the prepared baking sheet, ensuring they are not crowded for crispy edges.

Bake for 20 minutes. Flip the potatoes carefully using a spatula and bake an additional 15-20 minutes until golden and crispy.

Divide cooked potatoes into small portions and top each with warmed nacho cheese sauce and a dollop of sour cream.