Diana Nyad -- Big Fan of Oprah Shuffle

Diana Nyad had a lot on her mind at LAX ... for starters, she says it was awesome watching Oprah "shufflin' around" in The Butler."

In unrelated news ... she's trying to corral "cool people" like Jay Z for her charity swim ... but she kinda threw Richard Simmons under the bus in the process.

In more unrelated news ... Diana settles the age-old fear about swimming after eating.