In a medium bowl, combine beef, eggs, panko, and 1.5 tsp chili powder, kosher salt, and pepper. Roll meat mixture into 1.5-inch meatballs and transfer to a plate.
In a large nonstick skillet, add the olive oil and preheat to medium-high heat. Cook the meatballs, turning occasionally for a few minutes until brown. Return the meatballs to the plate.
In the same skillet as the meatballs, cook the red onion until tender. Next, add in the black beans, diced tomatoes, kidney beans, green chiles, water, tomato paste, cumin, garlic powder, salt, pepper, and remaining 1.5 tsp of chili powder. Stir to combine. Add the meatballs.
Bring the mixture to a boil and then reduce to a simmer. You want to simmer the sauce until slightly thickened, about 15 minutes. Check the meatballs occasionally to make sure they aren’t sticking to the pan.
Next, add the shredded cheese on top and place the pan until a broiler to get the cheese nice and golden brown. Remove from the broiler and top with all the garnishes!