I am not able to see Action card in edit option of NUX.
Please refer screenshot attached.
Apparently you won't find the 'Action' card in 'My Pages'.
You will need to create a standard Page, before you'll find the 'Action' card.
You will need page builder access to create a standard UX page for which contact your tenant admin , If you use 'My Page' it wont appear.
I second the above replies, check with your tenant admin that you have "page Builder" access and ensure you aren't building as a personal page. This should fix your issue.