Preheat your oven to 425°F. Line a baking sheet with parchment paper.
In a large bowl, toss the cauliflower florets with olive oil, chili powder, cumin, garlic powder, smoked paprika, salt, and black pepper until evenly coated.
Spread the cauliflower in a single layer on the prepared baking sheet.
Bake for 25-30 minutes, flipping halfway through, until the cauliflower is golden brown and crispy.
While the cauliflower is baking, warm the corn tortillas in a dry skillet over medium heat for about 30 seconds on each side.
To assemble the tacos, place a generous amount of the crispy cauliflower on each tortilla.
Top with shredded lettuce, diced tomatoes, red onion, and avocado slices.
Drizzle with sour cream or Greek yogurt and serve with lime wedges on the side.