Remove venison from skillet; keep warm. Stir marinade into skillet. Heat to boiling, scraping up any bits from bottom of skillet; reduce heat to medium. Cook about 5 minutes until mixture is slightly reduced. Stir in cranberries, jelly, butter and onions. Cook 1 to 2 minutes, stirring occasionally, until butter is melted and mixture is hot. Serve sauce with venison.