Preheat the oven to 475 degrees F and line a baking sheet with foil. Combine the chili powder, thyme, cayenne and 3/4 teaspoon each salt and black pepper in a small bowl. Rub the pork with 1 tablespoon olive oil and the spice mixture. Transfer to the prepared pan and roast, turning once, until a thermometer inserted into the center of the pork registers 145 degrees F, about 15 minutes. Transfer to a cutting board; let rest.
Meanwhile, combine the collard greens, 1 tablespoon olive oil and 1/4 teaspoon salt in a large bowl. Massage the greens with your hands until slightly wilted, about 1 minute. Add the black-eyed peas, Peppadews, scallions, vinegar and the remaining 1 tablespoon olive oil; season with salt and black pepper and toss to combine. Set aside.
Toast the crumbled cornbread in a small dry nonstick skillet over medium heat, stirring occasionally, until crisp, 3 to 5 minutes. Slice the pork and serve with the collard greens. Sprinkle the toasted cornbread over the greens.