Heat a large skillet over medium heat and add the oil. When the oil is heated, add the potato. Saute for about 7 minutes, stirring often, until beginning to get translucent.
Stir in the bell pepper, onion, and taco seasoning. Saute, stirring often, until the potatoes are fork tender, about 5 more minutes.
Whisk the eggs with the grated cotija. Push the hash mixture to one side of the pan and pour the eggs into the empty space. Use a wooden spatula or other sturdy utensil to scramble and cook the eggs, stirring often, until cooked through. Stir everything together in the pan.
Top with more cotija and other toppings such as avocado and cilantro!