Preheat the broiler. Pat the steaks dry. In a small bowl, mix the cumin and garlic powder with 2 tsp. salt and 1 tsp. pepper. Rub the mixture all over the steaks.
On a large rimmed baking sheet, toss the sweet potatoes with the oil. In another small bowl, mix the chipotle powder with 1 tsp. salt and 1/2 tsp. pepper. Sprinkle the chipotle mixture over the sweet potatoes and toss until coated. Arrange the steaks in the center of the baking sheet. Arrange the sweet potatoes in an even layer around the steaks.
Broil until the steaks are browned, turning the steaks and sweet potatoes halfway through, 8 to 10 minutes per side. Transfer the steaks to a cutting board and let rest for 10 minutes. If necessary, return the sweet potatoes to the oven and continue to broil until tender, 3 to 5 minutes.
Meanwhile, in a small bowl, mix the mayonnaise, sour cream, and hot sauce; season with salt and pepper. Sprinkle the steak and sweet potatoes with the cilantro and lime zest. Serve with the lime wedges for squeezing and the sauce for dipping.