Here are two links to help:
https://futurenowdetox.com/increase-nad-levels-with-diet/
https://www.springfieldwellnesscenter.com/mental-health-blog/how-to-increase-nad-levels-naturally/
The first link says a cup of Crimini mushrooms has over 3 mg of nicotinamide riboside.
Do note the capsule has either 150 mg or 300 mg, depending on which bought.
Thank you for the info.