Venison stir-fry with cashews and coriander

500 gDiced venison, cut into strips (Main)1 TbspSoy sauce1 TbspSesame oil, plus extra for cooking1 TbspRice wine vinegar1Garlic clove, crushed1Red chilli, deseeded and sliced1 headBroccoli, cut into florets and chunks (Main)2Spring onions, thinly sliced1 small bunchFresh coriander, roughly chopped2 TbspCashew nuts, roughly chopped (Main)1 tspBlack sesame seeds