Bring a large pot of water to a boil over high heat.
While the water is heating, cut the potatoes into ¾ inch chunks.
When the water is boiling, add the potatoes. Cook until they are just fork tender, approximately 15-20 minutes.
Drain the potatoes. Toss them with the vinegar, ½ teaspoon salt, and ½ teaspoon black pepper. Refrigerate until cool, at least 30 minutes.
While the potatoes are cooking or cooling, make the sauce in a large bowl. Combine the sour cream, mayonnaise, garlic powder, ground cumin, green chile powder (if using), and additional ½ teaspoon salt.
When the potatoes are cool and when you are ready to serve, in a large bowl combine the potatoes with the sauce mixture, celery, and diced green chiles. Season to taste if desired or needed.
Serve cold and garnish with additional peppers if desired.
