Preheat oven to 400. Line a large baking sheet with foil and spray lightly with cooking spray.
Peel butternut squash with a vegetable peeler or a sharp paring knife. Cut the squash in half, from top to bottom, and scoop out seeds. Cut squash into uniform cubes, about 1/4 inch.
Place cubed squash in a bowl and drizzle with oil, then lime juice. Add taco seasoning and salt and coat the squash thoroughly in mixture.
Spread squash evenly on baking sheet in a single layer. Roast 20 minutes. Turn, and roast again another 20 minutes, watching closely. You want them to be caramelized and crispy, but not burnt.
While the squash roasts, prepare your toppings and set aside.
Steam or fry your corn tortillas, according to your preference. No cold, rubbery tortillas allowed!
Just before ready to assemble tacos, place black beans in a microwave safe container, season lightly with salt and taco seasoning and heat in a microwave until hot, about 90 seconds.
Assemble tacos by taking a hot tortilla, topping with roasted squash, black beans, cilantro, onion, avocado, Cotija cheese, a dollop of sour cream, and a dash of hot sauce. Serve immediately.