My wife found this on QVC, it's delicious and makes it easy to dress a bunch of dogs in no time. I know it's not the classic Chicago format, but it delivers the right taste.
Chicago Style Hot Dog Relish
Serving Size: 8
1/2 large onion, quartered
3 dill pickle spears, quartered
2 plum tomatoes quartered and seeded
8 sport peppers, stemmed (or 8 pepperoncinis, stemmed)
3/4 cup sweet pickle relish
3 tablespoons yellow mustard
1/2 teaspoon celery salt
Hot dogs, and hot dog buns, for serving
Fit a food processor with a chopping blade and put the onion, pickles, tomatoes, and sport peppers in the bowl. Pulse the ingredients until they're finely chopped.
Transfer the mixture to a bowl and add the pickle relish, mustard, and celery salt. Stir to combine and serve on your favorite prepared hot dog. Makes about a pint.