Heat a large Dutch oven or other heavy, large saucepan over medium high heat. Add the ground chuck and onions and cook until meat is browned and onions are tender. Add garlic and cook for 2 minutes longer.

Drain the beef in a large sieve or colander, reserving the beef drippings on the side. (You will need the drippings later, so do not discard.)

Return the meat to the Dutch oven over medium-high heat and add the Rotel tomatoes, green chiles, diced tomatoes, Mexican chili powder, 1/4 cup regular chili powder, paprika, cumin, cayenne, salt, and oregano and stir until well-combined. Stir in the water, bring the liquid to a boil, cover the pot and reduce the temperature so that the liquid slowly simmers. Cook, covered and stirring occasionally, for 45 minutes to an hour. Taste and adjust the seasoning by adding more salt, chili powder, or cumin. The mixture should be overly seasoned since you will be adding cornmeal to it. Strain the mixture again in a fine sieve, pressing slightly to get some of the moisture from the meat; reserve meat and the spicy broth separately. 

Add 2 1/4 cups of the cornbread mix to the drained meat mixture along with 1 cup of the reserved meat drippings from when you originally sautéed the beef. Stir well to combine and then set aside to cool. Taste and season again with additional salt, cayenne, chili powder and cumin, if necessary. At this point the filling may be refrigerated for up to two days before rolling the tamales. The filling should be moist and somewhat sticky but not overly wet. If you have the time, it will be easier to work with the filling if allowed to sit for several hours or overnight.

Place the dried corn husks in a large bowl and cover with hot water, pulling the husks apart so that each husk is allowed to soften. The husks should soak for a minimum of 30 minutes or up to overnight. You can change the water and add more hot water if the husks seem too stiff to work with. The longer the husks sit in warm water, the easier they will be to work with.

When you are ready to roll the tamales, place the remaining 2 cups of cornbread mix and the remaining 2 tablespoons of chili powder on a plate or wide, shallow bowl and mix to combine.

Form each tamale by shaping about 2 tablespoons of the filling into a small log shape and then rolling it lightly in the chili-cornbread mixture to coat. As each tamale is rolled, transfer it to one of the long sides of a softened corn husk. Roll the corn husk up (side-to-side) around the filling, then fold up the narrower bottom portion of the husk, leaving the wider upper portion open. The mixture should come to within about 1/2-inch from the top edge of the corn husk -- it will expand as it cooks. Stack these rolled tamales on their sides (seam sides down so that they do not unfold) until you have rolled all of the tamales. Fill one large or two smaller high-sided pots with the tamales, folded ends pointing down, and fitting them snugly so that they hold each other upright but not so tight that there is no room for expansion. (Note: If you prefer, you can turn a large pot on its side and stack the tamales directly into the pot as they are rolled. Position the folded ends pointing down towards the bottom of the pot, fitting the tamales snugly against each other and filling the pot nearly to the top; leave a small amount of room for expansion. Then turn the pot upright and proceed as described below.)

Combine the spicy chile-broth with any remaining juices from when you sauteed the meat. Using a basting bulb or a narrow funnel, pour enough of this mixture into the pot (around the tamales but not over them -- you don't want the liquid to go into their tops). The broth should come within 1 to 1 1/2 inches from the top of the tamales. If it seems too low, add a bit of water to bring the level up.

Cover the pot and place it over medium-high heat until the broth is bubbling around the tamales. You don't want the broth to bubble into the open tops of the tamales, but it should be simmering near their tops. Lower the heat to low or medium-low and cook, covered, for 1 hour. Let the tamales stand for at least 30 minutes, then carefully remove them from the pot. Serve the tamales drizzled with any broth remaining in the pot and serve hot or warm. The tamales will continue to firm up as they cool and will be even more flavorful after sitting for several hours.