Can a pilot use glasses to meet the FAA required 20/20 vision?
It can be with correction. And note that for third class, distant vision only has to be correctable to 20/40. The near vision standard is 20/40 for all classes. See https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/ame/guide/standards/

As @Pondlife notes, the operative words here are,  "with or without correction."