In science, a theory refers to an explanation regarding elements of a specific phenomena.
They didn't. At no point in the trial was Nebraska man brought up by either side.
If you fail to find hard evidence that Nebraska man was mentioned, are you willing to admit that you were not only wrong but whatever sources you obtained this misinformation from were being dishonest?
Certain items of "scientific evidence of evolution" were mentioned at the trial, whether or not formally presented. This included Piltdown Man (announced to the world in December 1912, and repudiated in the 1950s when the British Museum's Kenneth Oakley devised a new method for determining whether ancient bones were of the same age), but especially Nebraska Man was proclaimed. The great Nebraska Man, discovered only three years before in Bryan's home state, was exalted at the trial as the outstanding evidence that man had evolved from an apelike creature.
"One of the most singular and embarrassing incidents in the history of evolutionary science began in 1922, when a solitary molar tooth was found in Nebraska. First-rank paleontologists, anthropologists and anatomists examined the cusp pattern, and all agreed with its discoverer that the tooth belonged to an ancient ape-man: a 'missing link' of tremendous importance, to which they gave the name Hesperopithecus a 'Western ape.'
"The tooth was certainly ancient; it was embedded in million-year-old Pliocene deposits. But what else could be said about it? For starters, English anatomist Sir Grafton Elliot Smith and a museum artist collaborated to produce a painting of both male and female Hesperopithecus for the Illustrated London News. Their 'reconstruction' featured full figures of a well-muscled, ski browed pair in a prehistoric landscape complete with early horses and camels.
"Professor H.F. Osborn, head of the American Museum of Natural History, welcomed the news. Antievolutionist politician William Jennings Bryan was a Nebraskan, and Osborn rubbed it in: 'The Earth spoke to Bryan from his own State,' he crowed, 'the little tooth speaks volumes. . evidence of man's descent from the ape.'
"In 1925, when John Scopes was tried for breaking Tennessee's state law against teaching Charles Darwin's theory of evolution in the public schools, the Hesperopithecus tooth was introduced as evolutionary evidence, along with other fossils, of early man [as] then accepted by science (including Piltdown, which was later revealed as a fossil forgery).
"Two years after the 'Monkey Trial,' a team of paleontologists returned to the Nebraska site where Hesperopithecus had been discovered five years earlier, determined to find more of this mysterious creature. To their joy, weathering had exposed parts of a jaw and skeleton on the precise spot. Eagerly, they brushed away dust and sand until the ancient fossil emerged to tell its truth, the infamous molar had once belonged to an extinct pig!" *A. Milner. Encyclopedia of Evolution (1990). P. 322.
In 1928, it was discovered that a mistake had been made and the "hominid tooth" of prehistoric Nebraska Man turned out to be nothing more than a pig's tooth! Three years after the Scopes Trial, one main "proof" of evolution had been destroyed.
In 1953, Joseph Weiner and Kenneth Oakley used a newly-developed fluorine test on the original Piltdown skull fragments, and discovered that the bones were a hoax! This became something of a national scandal focusing on the British Museum, although museum officials were probably only innocent dupes. Twenty-eight years after the Scopes Trial, the other main "proof" of evolution was destroyed.
"Two main lines of evidence for evolution [at the Scopes Trial] were the Piltdown man and Nebraska man. Nowhere in the trial did the scientific problems receive any sensible discussion. Darrow displayed ignorance both about the theory of evolution and the teachings of the Bible, and leveled a barrage of insults and vilification at fundamentalist Bryan. Bryan did not respond in kind. Darrow was clearly the media favorite, however." Michael Pitman, Adam and Evolution, p. 100.
"Some thought that reports of what occurred at the trial would damage the cause of evolution. However, on the contrary, the evolutionists have used it to state repeatedly that although Darrow 'lost' the trial, he 'won' the case and that since the time of the Scopes Trial, no intelligent person can any longer doubt the truth of evolution.
"However as time has passed, the 'scientific' evidences against evolution have increased both in number and in strength. There is more that can be said against an evolutionary belief now than there has been at any time in the past because more facts are known and more evidences against evolutionary theory are constantly coming to light." Donald W. Fatten, "The Scopes Trial," in Symposium on Creation III (i971), p. 117.