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