No. Portfolio layouts are responsive to fit on mobile, tablet and desktop devices without horizontal scrolling. Vertical scrolling is preferred by more users.
Feel free to leave a feature request on Adobe UserVoice. If it's viable and enough other people agree with your idea, it might get added later.
More Portfolio links:
- FAQ & Knowledgebase for product help - https://help.myportfolio.com/hc/
- Contact Portfolio Support for technical help - https://help.myportfolio.com/hc/requests/new?ticket_form_id=177168
- Adobe UserVoice for feedback & bug reports - https://helpx.adobe.com/x-productkb/global/how-to-user-voice.html
EDIT: Portfolio on UserVoice has been deactivated. Please submit feedback to the Portfolio Support Team.
https://help.myportfolio.com/hc/requests/new?ticket_form_id=177168