Would it be legal and ethical for the president of the U.S. to privately discuss a cabinet position with the intended person before officially nominating?

Suppose, for example, that the Democrats win in November and the new president would like to give Elizabeth Warren a cabinet position, but is not certain whether she would accept. Would it be okay to discuss this with Warren beforehand to avoid a possibly awkward situation? It seems to me that there should not be anything wrong with this.