Season the chuck with 1 1/2 teaspoons of the salt and blot it dry with paper towels.
Heat the oil in a large skillet over medium-high heat and brown the beef in 3 batches for about 5 minutes per batch, leaving space between the cubes.
Cook the onion in the same skillet for 5 minutes, then stir in the garlic, ancho powder and cumin for 30 seconds.
Transfer everything to a 6-quart crockpot, add the tomatoes, beans, broth and remaining salt, and cook covered on low for 7 to 8 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 cook uncovered on high for 30 minutes until the broth coats the beef.