In a medium mixing bowl, combine ground bison, panko bread crumbs, egg, milk, minced onion, salt and pepper. Mix well, then roll into 1 1/2 inch meatballs balls and place in rows on a rimmed baking sheet.
Airfry at 400 degrees for 20-25 minutes, or until fully cooked through.
In a large saucepan, combine ingredients for sauce. Bring to a boil, lower heat, and simmer until sauce is thickened and reduced.
Add the meatballs to the saucepan and stir to coat.