Preheat your oven to 425 degrees Fahrenheit. Line a baking sheet with foil and spray with nonstick cooking spray.
Prepare the cauliflower by washing and chopping it into bite-sized florets. You can also use pre-cut bags of cauliflower florets.
To a small bowl, add the ground chipotle chili powder, paprika, garlic powder, ground cumin, ground coriander, salt, and cayenne pepper if you like spicy. Pour the avocado oil over the seasoning and stir well to combine.
Toss the cauliflower florets in the seasoned oil until they are coated and arrange them in a single layer on the prepared baking sheet, do not crowd. Use 2 sheet pans if necessary.
Roast the cauliflower at 425 degrees Fahrenheit for 25 - 30 minutes, stirring halfway through.
While the cauliflower is in the oven, make the Fiesta Lime Coleslaw. (see notes)
To build your tacos, you can use warm flour or corn tortillas, or even healthy tortilla alternatives. Spoon the roasted cauliflower onto the tortillas. Add the slaw and any additional toppings that you would like. Serve immediately and enjoy!