Season the chuck with 1 1/2 teaspoons of the salt and pat it dry.
Heat 1 tablespoon of the oil in a Dutch oven over medium-high heat and brown half the beef for 6 minutes; repeat with the remaining oil and beef.
Lower the heat to medium, add the onion, and cook for 5 minutes until translucent before stirring in the garlic, ancho powder, cumin and tomato paste for 1 minute.
Return the beef, add the broth and remaining salt, and simmer partly covered for 2 hours until the beef is fork-tender and at least 145°F.
Whisk the masa harina with the warm water, stir it into the chili, and simmer uncovered for 10 minutes until the sauce clings to the beef.