No, it wasn't Einstein (who didn't receive his Nobel Prize for the theory of relativity anyway). Albert Michelson received the Nobel Prize in 1907 and showed up as a character on the show Bonanza in 1962.
Michelson is famous for the Michelson-Morley experiment, which was designed to measure the change in the speed of light due to the motion of the earth. However, the experiment actually failed to detect any change, since the speed of light is the same no matter how fast you are moving relative to the light.
Michelson grew up in Nevada, where Bonanza was set. In the show, Ben Cartwright (Lorne Greene) gets the young Michelson an appointment to the Naval Academy, thus setting in motion the train of events that would lead to Einstein's theory of relativity. Who would have guessed?
It's a little-known fact that the Cartwrights also had a daughter, Angela, who would later take part in the first manned mission to Alpha Centauri.