Put diced potatoes in a saucepan and add enough water until the potatoes are just covered. Bring the potatoes to a boil over high heat, and then reduce to a simmer. Simmer the potatoes for 20 minutes then add in the ground beef, onions, and green chiles. Let the stew continue to cook until the potatoes are fork tender and the beef is cooked all the way through, another 10 to 20 minutes. Season the stew with garlic salt and serve warm.