Heat oil in a large nonstick skillet over medium heat. Add tomatillos, onion and garlic and cook, stirring, until most of the liquid from the tomatillos is evaporated, 8 to 12 minutes. Add eggs, pepper and salt and cook, stirring, until the eggs are just set, 2 to 3 minutes more. Divide the scrambled eggs among the tortillas and sprinkle with cheese.