Preheat oven to 350 degrees.
Cook ground beef over medium heat, breaking it up as it cooks.
While beef cooks, slice the 3 bell along their septums into 3 parts, then cut each of those 3 parts in half, and set aside.
Chop the tomato and onion finely, and add to a large mixing bowl.
Once beef is no longer pink, drain most of the fat and add ground beef to the bowl with the vegetables.
Add to mixing bowl the chilli powder, cumin, black pepper, and salt. Mix until all ingredients are combined.
In a greased baking dish, line up the bell pepper parts, and spoon in the beef mixture.
Top each nacho boat with grated cheddar cheese.
Bake for 20 minutes, then remove from oven and set oven to broil.
Broil for 5 minutes or until cheese is golden.