Sierra's links give the recipe for a sauce with meat. Sounds great.
Being ex New Yorkers, though, we remember Sabrett stands. Loved the dogs, but craved the sauce. Here is a copy cat recipe that I have messed about with enough to avoid any copyright problems.
1 and 1/2 teaspoons olive oil
1 onion, medium, cut thinly and chopped (you don't want diced here, you want thin threads of onion)
2 cups of water
1 tablespoon corn syrup
2 tablespoons tomato paste
1 teasppon cornstarch
1/2 teaspoon salt
1/4 teaspoon red pepper flakes
1/4 cup vinegar
Saute the onions in the oil until they are soft. You definitely do not want them to brown.
Toss in everything else, except the vinegar and let simmer (OK, a brisk simmer, if such a thing is possible, maybe a gentle boil would be a better term).
Let it do this until it is thickening, toss in the vinegar and let it go until it has a fairly thick consistency.
The final product should have threads of onion in a thick sauce.
Have not been back to NYC for several years, but it seems the Sabrett stands have been replaced by another type of hot dog.
The dogs are OK, but we miss the sauce.
This would not be too good on nachos I fear, but it does ring our bell on dogs.
Take care and God bless.