Preheat the oven to 425°F (220°C). Line a large baking sheet with parchment paper if desired.
Place the diced sweet potatoes on the baking sheet. Drizzle with 2 teaspoons olive oil.
Season the sweet potatoes with ½ teaspoon chili powder, ½ teaspoon garlic powder, ½ teaspoon cumin, smoked paprika, ¼ teaspoon salt, and black pepper.
Toss thoroughly until the sweet potatoes are evenly coated, then arrange them in a single layer.
Roast for 22–25 minutes, turning once if desired, until tender inside and lightly browned around the edges.
While the sweet potatoes roast, pat the chicken breasts dry with paper towels.
Season the chicken with the remaining 1 teaspoon chili powder, ½ teaspoon garlic powder, ½ teaspoon cumin, onion powder, and ¼ teaspoon salt.
Heat the remaining 1 teaspoon olive oil in a large skillet over medium heat. Add the chicken and cook for approximately 6–7 minutes per side, depending on thickness, until the center reaches 165°F (74°C).
Transfer the chicken to a cutting board and let it rest for 5 minutes before slicing or dicing.
Prepare the sauce by whisking together Greek yogurt, salsa, lime juice, water, chili powder, garlic powder, cumin, and salt until smooth.
To assemble the Tex-Mex Chicken Sweet Potato Bowl, divide the chopped romaine among four bowls.
Add roasted sweet potatoes, sliced chicken, black beans, corn, cherry tomatoes, red bell pepper, red onion, shredded cheese, and fresh cilantro.
Drizzle each bowl with creamy Tex-Mex yogurt sauce and serve with fresh lime wedges.