Preheat the Traeger to 225°F with the lid closed. Line a rimmed baking sheet with parchment paper or foil.
In a large bowl, whisk the egg with 2 tablespoons of the ketchup, the minced chipotle, and the adobo sauce. Stir in the cumin, chili powder, salt, and black pepper.
Add the ground beef, breadcrumbs, black beans, corn, red bell pepper, and red onion. Mix gently until combined, taking care not to mash the beans or overwork the beef.
Shape the mixture into a compact loaf on the prepared baking sheet. Place it on the Traeger and smoke until the center reaches 150°F, about 1 1/2 to 2 hours depending on the loaf’s thickness.
Spread the remaining ketchup over the top and sides of the meatloaf. Increase the Traeger temperature to 350°F and cook until the center reaches 160°F on an instant-read thermometer.
Remove the meatloaf from the grill and let it rest for 10 minutes before slicing. Resting helps the slices hold together.