Brown the beef and onions together in a large pot over medium heat until beef is cooked through and onions are soft. Once cooked through, you can drain the fat if you like.
If not, go ahead and add everything else into the pot (as easy as that). You may want to melt the chocolate before adding it, but it might not make a difference, up to you. You also may want to start with less seasoning than the recipe calls for and adjust to taste, especially after allowing it to simmer for some time.
Let simmer on medium-low heat for 45 minutes to an hour, or until flavors blend together. Serve with plenty of green onions, cheddar cheese (or any cheese of your choice -- I used smoked gouda because that was what we had and it was amazing), and more jalapenos if you like.