Nichols

Doctor Nichols was a plant manager in 1986 at Plexicorp in San Francisco.

In exchange for use of his facilities to build walls for his whale tank, Montgomery Scott gave him the formula for transparent aluminum. Scott brushed off concerns that this would result in a change of the timeline, asking "how do we know he didn't invent the thing?". Nichols had recently quit smoking prior to Scott and McCoy's visit. (Star Trek IV: The Voyage Home)

In the novelization, Scotty is described as knowing that history does, in fact, record that Dr. Nichols is the inventor of transparent aluminum, and hence that Nichols was meant to receive the formula from him.
Nichols was played by Alex Henteloff.

According to the novel The Rise and Fall of Khan Noonien Singh, Volume 2, he patented transparent aluminum and passed it off as his own invention, eventually earning enough money to buy Plexicorp from its original owners. As a result of his work in the field of cryonics, he was recruited by Area 51 to assist in the construction of the DY-100 prototype vessel in March 1993.