Did you mean access the suggestions from Opportunities tab in the UI through AdWords API? If so, I'm afraid there is currently no way to fetch these suggestions using the AdWords API.
However, the AdWords API supports
bid landscapes which helps you estimate the performance of your adGroups, criteria, and campaigns if you made some changes in the bid. Also, the API provides the
TrafficEstimatorService which can help estimate traffic for existing adGroups and campaigns.