Add the spinach, garlic, ground beef, taco season, and broth to the pan. Break up the beef, and cook the veggies, beef, and broth together for over medium high heat, until the broth comes to a simmer. Reduce the heat to a low simmer, stirring occasionally until the beef is cooked through, and the broth is reduced all the way down so that the taco mixture isn't runny. This takes about 10 minutes.