Hi Mike -- thank you for posting to History Hub!
The 'Nelson Pill Hearings' were held by the Senate Select Committee on Small Business, Subcommittee on Monopoly (of which Senator Gaylord Nelson was Chair), in the early 1970s.
The transcripts of these hearings were published in three volumes:
- Competitive Problems in the Drug Industry, Part 15: Oral Contraceptives (Volume One). Jan. 14, 15, 21-23, 1970 -- Y4.Sm1/2:D84/pt.15
- Competitive Problems in the Drug Industry, Part 16: Oral Contraceptives (Volume Two). Feb. 24, 25, Mar. 3, 4, 1970 -- Y4.Sm1/2:D84/pt.16/v.2
- Competitive Problems in the Drug Industry, Part 17: Oral Contraceptives (Volume Three). Appendices. 1970 -- Y4.Sm1/2:D84/pt.17/v.3
Regarding audio, I don't see any indication that the Center for Legislative Archives (the unit within the National Archives that holds the records of Congress), has any A/V material from the Senate Select Committee on Small Business in the 91st Congress.
The responsibility for filming public hearings generally falls to C-Span and the news media. Copies of that footage rarely, if ever, end up in the official records of congressional committees.