In a large pot, brown the ground beef (or turkey) over medium heat until fully cooked, about 5-7 minutes. Break it up with a spatula as it cooks.
Add the diced onion and garlic to the pot, cooking until the onion is translucent, about 3-4 minutes.
Stir in the taco seasoning, mixing well with the meat and onions. Let it cook for a minute to enhance the flavors.
Pour in the diced tomatoes with their juices, black beans, and corn, stirring to combine.
Add the spaghetti and broth to the pot. Make sure the spaghetti is submerged in the liquid. Bring to a boil.
Once boiling, reduce the heat to low, cover the pot, and let it simmer for about 12-15 minutes, or until the spaghetti is al dente and most of the liquid is absorbed. Stir occasionally.
If there is any excess liquid, remove the lid and let it cook for an additional 2-3 minutes, stirring gently.
Remove the pot from heat and sprinkle the shredded cheddar cheese over the top. Cover for a few minutes to melt the cheese.
Season with salt and pepper to taste.
Serve hot, garnished with fresh cilantro and sliced jalapeños if desired.
Notes
Feel free to adjust the spice level with more or fewer jalapeños.