2. Step
Heat oil in a large nonstick skillet over medium heat. Add sweet potatoes; cook, stirring occasionally, until just tender on the outside, 10 to 12 minutes. Add chili powder, cumin, salt and pepper; cook, stirring constantly, until fragrant, about 30 seconds. Stir in tomatoes and green chiles; cook, stirring occasionally, for 1 minute. Remove from heat; stir in black beans, corn and 3/4 cup cheese.