Chicken, Sweet Potato, and Corn Tacos

2 tablespoons olive oil

16 ounces chicken breast tenders or ground turkey, or 15-ounce can black beans, drained

2 teaspoons chili powder 

1 teaspoon cumin

1/2 teaspoon salt

¼ teaspoon black pepper

2 sweet potatoes, peeled and diced

10-oz frozen corn

2 tablespoons lime juice

8 small tortillas (flour or corn) 

¾ cup of shredded mexican-style cheese (Monterey jack or any blend)

1/4 cup salsa