Pot Roast Tacos with Horseradish Sauce

organic chuck roast

garlic powder, onion powder, kosher salt and pepper

olive oil

envelope dried onion soup mix (I use Simply Organic)

tamari (or soy sauce)

chicken stock

yellow onion, peeled and thinly sliced

garlic, minced

corn tortillas

vegetable oil

sour cream

prepared horseradish

kosher salt