Comedian, actor and former mechanical engineer William Sanford Nye (b. 1955) is best known for the show Bill Nye the Science Guy (1993–98). Nye gave a very poor response to the question regarding radiometric dating in the recent debate with Ken Ham (see the 2 hour and 7 minute mark).
First, he side-stepped the issue and brought up old stars. That’s right, he was dancing with the stars! Russell Humphreys (Ph.D. Physics, formerly with Sandia National Labs) wrote Starlight and Time in 1994 and gave a plausible answer to this question based on the General Theory of Relativity and gravitational time dilation. A reasonable man or woman can see that the light travel problem applies to both the Big Bang and Creation models (as Ken pointed out regarding the horizon problem).
Nye defended an old earth based on depositional rates. In 1883, Alexander Winchell, former State Geologist of Michigan, estimated the age of the earth at 3M years.  That’s a far cry from 4.5 billion years. That was back when gradualistic uniformitarianism was in vogue. But now catastrophism has a wide following even within mainstream Geology. So, if most deposits were formed rapidly, such as turbidites, the depositional rates favor Young Earth Science (YES).
Nye said Charles Lyell (d. 1875) came up with the phrase “deep time.” Actually, it was John McPhee who wrote Basin and Range in 1980. McPhee said, “The human mind may not have evolved enough to be able to comprehend deep time” (p. 133).
Marie Skłodowska-Curie (d. 1934) came up with the term “radioactivity.” Nye made the very common mistake in stating that radioactivity contradicted Kelvin’s age for the Earth (his final estimate was 24M). In 1895, before the discovery of radioactivity, John Perry showed that convection in the Earth's interior modified Kelvin’s age of the Earth.
Some claim that YES is pseudoscience. Bill Nye the Science Guy had an episode on that topic. Nye said there must be aliens because there are so many stars. Yet no one has seen aliens and there are no cities on Mars. Extraordinary claims (aliens) require extraordinary evidence. Nye was skeptical of the Loch Ness Monster. According to the Smithsonian’s online encyclopedia, “Even though most scientists believe the likelihood of a monster is small, they keep an open mind …” Perhaps Nye should be open minded towards YES. An article in National Geographic was very fair towards Nessie and included reports from very reliable witnesses. 
Nye should read Kicking the Sacred Cow by former aeronautical engineer and award winning SciFi author James Hogan. Hogan is very sympathetic to YES. Ken Ham sent Nye a book in The New Answers Book series – will Nye have an open mind and read it and seriously consider the evidence?
As for the question posed to Nye in the debate, Ephraim Fischbach (Purdue University) gave a talk at the Institute for Theoretical, Atomic and Molecular and Optical Physics (Harvard-Smithsonian Center for Astrophysics) providing firm data that indicates that the sun affects radioactive decay rates. John Woodmorappe (M.A. Geology) has written an excellent book refuting radiometric dating and millions of years. Jay Wile (Ph.D. Nuclear Chemistry, Univ. of Rochester), at one time a skeptic regarding accelerated radioactive decay, has some great info on varying decay rates.
Soft tissue in dinos, as discovered by Mary Schweitzer and others, says that dinos are young and the dating methods are wrong. As Tim Stafford (The Adam Quest) asks, “How could something as delicate as blood cells survive sixty million [sic] years?” 
Pray for Bill. The Apostle Paul persecuted the church. Bill is persecuting YES. Paul was gloriously converted (Acts 9, 22, 26). The same thing can happen to Bill! Will Bill Nye the Science Guy be blinded by the light (Acts 22:11)?
Nye is the head of the Planetary Society. Feel free to send him a letter of encouragement or some creation books (such as the New Answers Books):
Attn. Bill Nye
The Planetary Society
85 South Grand Ave
Pasadena CA 91105
1) "Celebrating the age of the Earth" by Simon Knell and Cherry Lewis, Geological Society, London, Special Publications, 2001, vol. 190, p. 1-14, p. 7.
2) “Loch Ness: the lake and the legend” by William Ellis, National Geographic, Vol. 151, No. 6, June 1977, p. 759.
3) The Adam Quest by Tim Stafford (Nelson Books, Nashville, TN, 2013), p. 105.