What actor has the most Oscar nominations for his performances?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'INTERNAL', 'name_': 'Q103916', 'id': 0, 'label': 'Academy Award for Best Actor'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q19020', 'id': 1, 'label': 'Academy Awards'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q39792', 'id': 2, 'label': 'Jack Nicholson'}], 'links': [{'name_': 'P31', 'source': 0, 'target': 1, 'label': 'instance of'}, {'name_': 'P1346', 'source': 0, 'target': 2, 'label': 'winner'}, {'name_': 'P166', 'source': 2, 'target': 0, 'label': 'award received'}]}