1 medium onion, sliced
4 cloves garlic, minced
1 (10 ounce) can peeled and diced green chilies, drained
1 (20 ounce) can diced green chilies, drained
1 cup vinegar
1/2 cup chopped fresh chilies, or to taste
1 teaspoon chili powder
1 teaspoon salt
In a large saucepan, layer the sliced onion. Cook over medium heat until thickened. Add the garlic and saute until translucent. Stir in green chile peppers, tomatoes and vinegar.
Stir in chilies, toss with chilies and chili powder. Cook over medium heat (do not brown) for about 20 minutes, or until al dente; cool completely.