Preheat oven to 400 degrees F and line a baking sheet with foil or parchment paper.
Toss sweet potatoes in a bowl with olive oil and salt, until evenly coated. Pour onto the prepared baking sheet and roast for 25-30 minutes, until softened and lightly crisp on the edges. Remove and allow to cool.
Meanwhile, add 2 teaspoons of oil to a large skillet over medium-low heat. Add in chorizo, and cooking, stirring and crumbling, until it is cooked and not soupy looking. Drain grease and return pan to burner.
Add roasted sweet potatoes and black beans. Stir to combine and allow to heat through.
Warm tortillas, fill with chorizo mixture and top with green onions, cotija and a squeeze of fresh lime juice, plus any other toppings you like!