I wouldn't list it under job experience for all the reasons others have said. So don't try to list "Beta Tester, October 2020 to present, Company under NDA" or anything like that.
If you have a section on your resume where you list keywords of applicable skills, I think it'd be OK to list it as a generic skill: "Skills include: Unix, Microsoft Office, beta testing, agile methodologies..."
Then if it comes up during an interview, I think you could talk about it generically, like that you wrote up bug reports, or did weekly status reports, or helped with product installation, or whatever. Obviously stay away from any specifics about the product or the company, and maybe not even the industry. If they ask for anything too specific I think you could just say that your current work is under NDA and expect them to understand that and be OK with it.
(I've been involved on the company side of software R&D and testing for a Dow 30 tech company's beta testing program, and was also involved in hiring for them and another S&P500 tech company. I'd add that generally, beta testing is a nice to have, but it's probably not going to move the needle a great deal in any case. So even if you don't list it, you're probably not hurting your chances much if at all.)