Preheat oven to 350 degrees F (175 degrees C). Spray a small roasting pan with cooking spray.
Combine ground beef, 1/2 can chowder, onion, eggs, celery, bread crumbs, parsley, salt, and pepper in a bowl; mix until smooth. Mound meatloaf mixture in the prepared roasting pan. Cover pan with aluminum foil.
Bake in the preheated oven until no longer pink in the center, about 1 hour.
Remove from oven; pour remaining 1/2 can chowder over top and sides of meatloaf. Return uncovered pan to the hot oven; bake until an instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C), about 30 minutes more.
