MIX the chili kit spice packet contents (reserve the masa harina, granulated onion and garlic for later) and the chuck roast, coating well. Let marinate for at least 30 minutes.
HEAT 2 tablespoons of the vegetable oil in a large Dutch oven over medium-high heat. Sear the beef, in 2 or 3 batches, cooking until golden brown on all sides. Transfer beef to a bowl or platter.
ADD remaining 2 tablespoons of vegetable oil to Dutch oven and, when hot, add the Hatch chili, jalapeno and Fresno peppers; stir and cook for about 3 minutes. Season to taste with salt.
ADD beef and any released juices back to the pot, followed by broth, brown sugar, vinegar, Worcestershire sauce and the Chili Kit onion and garlic packets. Bring to a boil, then immediately reduce heat and simmer, cooking partially covered and stirring occasionally, for 2 hours. The beef should be tender, with a slightly thick sauce. (If a thicker sauce is desired, mix the Chili Kit masa harina packet with a small amount of water and whisk it into the chili and cook for a few minutes longer.)
SERVE chili topped with green onion, cilantro and a dollop of sour cream.